Rough Evaluation Class

faceting rough evaluation

“Buy as a skeptic, sell as an optimist!” – J.B.

There are certain desirable traits in Faceting Rough. Mainly, one wants Good Color, Good Shape, Good Size and Good Clarity.

Good Color:

“Pretty” is in the eye of the beholder, but generally, the eye will automatically find the most expensive stones. That demand, across many viewers, is what makes a given facet rough expensive – demand. Color is 60% or more of the value in any colored stone, so look at color carefully, in various kinds of light. Stones will likely appear differently under fluorescent than incandescent or sunlight…

Good Shape:

Generally, you want a faceting rough stone that’s “blocky” or “chunky” or “rounded”. Flat or twisted shapes or faceting rough with deep pits or valleys will yield very poorly. Here’s an example of a badly-shaped facet rough:

faceting rough aquamarine

The long, pointed end on the left of this will waste, as will the thinly flattened end on the right. Only a very small portion of this stone can be recovered by faceting.

Good Size:

Everyone has a claim about the yield of a gem rough. Facet rough dealers often say you’ll get a 1-carat stone from a 2-carat faceting rough. And, some cutters claim such feats on a regular basis, but any cutter who keeps records of actual weights knows the truth – that the industry standard for commercial cutting is a 20% yield (an 80% loss of weight) is average.

Pencil everything conservatively, using the 20% yield, and you won’t go too wrong. If you want a 1-carat stone, then buy a facet rough of at least 5 carats (one gram) weight. If the dealer is selling by-the-carat, then divide by five to find the likely finished carat weight. If they’re selling by-the-gram, then number of grams in equals number of carats out. (There are five carats in one gram.) This is fundamental in understanding what to expect from your gem faceting rough.


You want a stone that’s “clean” of inclusions and flaws – Flaws are cracks or voids or open cleavages or other things that compromise not only the appearance, but also the structural integrity. A flaw breaching the surface of a finished stone is doubly bad because it hampers light at the surface as well as internally. Inclusions are foreign matter within the rough gem. Such things absorb light and interfere with the optics of a gem.

A perfectly clean stone is difficult to find, and is not necessarily the target. The object is overall presentation and beauty – even if an inclusion is highly visible or even made into part of the presentation. However, in general, flaws and inclusions are things we like to avoid in the purchase, or to remove in the cutting.

Your Toolkit:

The “basic” toolkit can grow out of hand (and out of budget) quickly, so this setup is the very most basic, and can be assembled for under $35:

  • Loupe ($10 and up, depending)
  • Lamp with solid opaque shade ($10 and up)
  • Fluorescent Light (probably free in your kitchen)
  • Incandescent Light (probably free in your den)
  • Sunlight (free)
  • Tweezers ($5 and up)
  • Glass of water (free, in your kitchen)
  • White paper (free, in your kitchen or bathroom)
  • Time, attention, and patience

All of the following critical tests and evaluations can be performed with the above, and some practice.

Your Gem Testing Checklist:

Each of these items is important, and requires detailed explanation:

Confirm Identification:

It’s important to know what kind of stone you’re buying or selling. Identification of gem materials is a complex science, and a lifelong study. Know that your dealer knows the stones he’s selling you and learn all you can to protect yourself.

Here’s a photo of a crystal that a dealer sent as “Fluorite”:

faceting rough aquamarine

Note the shape of the crystal is hexagonal.
(Fluorite does not make hexagonal crystals.)

faceting rough aquamarine

Note the metal from a dinner-fork tine that I used to attack the surface of this stone. Note that the stone ground away metal – The metal did not scratch the stone. What do you think this crystal is?

Identification is an ongoing issue if you’re buying rough. Read, look, test, learn, repeat.

Check Size:

Size can be “bad” if the rough won’t support a stone that is marketable or that is “a good deal” after you count the cutting costs. For instance, a plain red Almandine Garnet rough weighing one gram will finish a gem weighing about one carat. Retail price for a one-carat commercially-cut red Almandine is far less than I’d charge to cut it. So, unremarkable red Almandine Garnet in one-gram sizes is not an investment. It seems size really does count…>

Check Shape:

Roughs that are broken or shaped with long, skinny points, flat areas, or divots should be avoided. They will yield very poorly.

What color is oval?

Color can be directional (read more below). Make certain to notice how direction of color may affect the usefulness of a rough’s shape! For more information on shape issues, study my page on geometry.

Test Color:

Color can be “bad” in three different ways:

  • Too Dark
  • Bad Dichroism, or a Closed C-axis
  • Bad Color Modifiers

These things require a detailed explanation, so let’s take each one in order:

1. Color Too Dark:

You’ll find most rough dealers on the Internet photograph their pieces with strong back-lighting. Back-lighting shows clarity, but is deceptive with respect to color. Stones that have nice color when back-lit will often be too dark when faceted. Detect the “too dark” problem using the “white paper test“.

facet rough tourmaline

This stone may look beautiful here, but click on the photo to learn about the test that will prove it’s a real dud – and why you should not buy stones based on the color you see in such photographs.

2. Bad Dichroism, or a Closed C-axis:

Many stones are dichroic, which means they show different colors in different directions. Some gems with this ability will show nearly identical colors in all directions, while some will show only differences in color density (darker or lighter). However, some will show drastically different colors – such as red in one direction and green in another. This can be a prized feature or it can be a nightmare.

tourmaline facet rough

This stone may look beautiful here, but click on the photo to learn about the test that will prove it’s really yucky – and how to guard against buying worthless stones like it.

Which way is red?

Imagine that a stone has a strong red color (desirable) in one direction and a weak pink color (not as desirable) in another. This is typical of Oregon Sunstone! Now, imagine that the stone is much better shaped for yield in the direction that shows weak color, and very skinny in the direction that shows the desirable strong red color. Again, this is typical of Oregon Sunstone! In stones that have directional color (Sunstone, Iolite, Sapphire, Tourmaline, and many more), an interplay of shape and color-direction will drastically affect yield and value! Research the specific gem you’re interested in, and look carefully at how color and shape relate before you spend!

Tourmaline is one stone that often has extreme dichroism, a variation of which manifests as “closed C-axis”. This means that light will not pass through one axis (direction) of the stone at all. Because light must pass in every direction for most gem designs to sparkle, the closed C-axis condition can render a Tourmaline worthless, and in almost any case should drastically reduce the price of the rough stone. Detect the “bad dichroism” or “closed C-axis” problems by using the “Look all around for color test“.

tourmaline faceting rough

This stone may look beautiful here, but click on the photo to see how simply looking from a different angle will prove you shouldn’t buy it – or any others like it.

3. Bad Color Modifiers:

Colored gems show the main color you see when you first look, but when you look closely you may notice the secondary color or tint – a modifier. This modifier can be any other color from grey to yellow, brown, etc. If the modifier is an unpleasant color – or if the combination of the modifier and the main color is unpleasant, then the price of the stone will drop accordingly. Remember that color is 60% or more of a colored stone’s value. Detect the “bad color modifier” problem by using the “white paper test” and the “Look all around for color test”.

Test for Flaws and Inclusions:

These problems are more common in some stones than others, but should always be searched for. Flaws can cause a stone to come apart during cutting – resulting in a broken heart as well as a broken stone! Flaws can seriously impair the presentation, interfering with light transmission or causing unwanted reflections, etc., and drastically affecting clarity, which is a huge factor in stone value.

aquamarine faceting rough

Here, a flaw deep within this Beryl (arrow) is reflecting light brightly. Can you spot any of the other flaws in this stone?

Inclusions can be found in almost any natural stone – if you use enough magnification. They can be a problem when eye-visible to the casual observer, or when loupe-visible to the connoisseur – depending on your reason for buying the stone, and the level at which you want to play this game. Not all inclusions subtract from value. Oregon Sunstone often benefits from decorative schiller inclusions, and Demantoid Garnet is more desirable if it has “horse-tail” inclusions.

tourmaline faceting rough

This Tourmaline crystal shows many inclusions. Click the image to learn how to do this test properly.

The above exceptions aside, we’d prefer stones that don’t have eye-visible inclusions because they usually detract from presentation and value. However, some kinds of stones such as Emerald, for example, nearly always have some inclusions. Do some research and know what to expect in the specific gem you’re shopping for! Detect inclusion problems using the following three tests:

Gem Testing Techniques:

How to Check Size:

Look up prices, and check reasonable weights for the size stone you want. (Colored stones are measured in millimeter sizes, but sold by the carat.) Use a reasonable reference source for your research. If you’re shopping garage sales, then use a garage-sale-grade market such as e-bay. If you’re shopping quality custom gems, then shop custom cutters. If you’re shopping retail-commercial-grade stones, then visit your local jeweler.Find out what a stone the size and cut you want will probably weigh. Multiply by five to find the weight of rough you’ll need to shop for. Don’t shop for a pint if you really need a gallon!

Look All Around (for color, NOT inclusions):

Focus on one thing at a time! If you’re doing a color survey then keep color on your mind and forget all else for the moment. Look through the stone from every direction – especially if the stone you’re shopping is known for directional color. Look in every direction, using different lighting sources.

If you’re testing for color direction, you can use back-lighting, but remember to use the “white-paper test” for color quality and density. Take special note of any directionality to the color – and examine how that relates to stone shape (remember yield).

facet rough tourmaline

This Tourmaline looks like it could make a beautiful Pear (left photo) – until you check the other direction (right photo) – and see the dark, bile-green color. If you cut this stone for size alone, it will face-up this ugly color. If you cut the stone for the smaller pear-shape, the beautiful teal will be polluted with enough vile overtone to drastically affect the appearance and value. This is what we call leaverite…

Even if the proportions were reversed, and the pretty color were in the long dimension, there would still be concern about the presence of the darker, and less-pleasant color on the C axis. The following photo shows a finished gem with such a condition.

faceted tourmaline

Even though the design of this gem was created to maximize the desirable color, one can clearly see the darkening and yellowing toward each end of the stone. Whenever shopping Tourmaline or other strongly dichroic gems, always check the desirability of color in every direction. Reject stones with undesirable colors on the C axis as you would closed C axis (unless the stone is long and pencil shaped as in this study).

If you’re shopping a Tourmaline, insure that the C-axis is open – or that the shape will allow you to work with the stone even if it isn’t. Always look in every direction to insure you’ve checked well.

facet rough tourmaline

Two views of the same Tourmaline crystal – one showing beautiful color, and the other showing the closed C axis. This stone cannot be cut to produce a good-quality gem.

White-paper test (for color, NOT inclusions):

Stay focused on one characteristic of the gem at a time. This test is for color ONLY. Place the stone on a white sheet of paper and observe it at a 45 degree angle while lighting from a 45 degree angle from behind. Reflect light off the paper and through the stone toward yourself. Do this test with all three kinds of light (incandescent, fluorescent, and daylight). DO NOT lower the angle to pump more light through the stone – Remember to buy as a skeptic and sell as an optimist.

facet rough tourmaline

Here are two photos of the same rough – One in the aggressively back-lit style of most Internet dealers, and the other in “white-paper test” lighting that shows the amount of color you can realistically expect after faceting. This stone “fails” the white-paper test – no sale!

If light reflects off the paper and through the stone then this is the approximate color and color-depth that you’ll get from a stone in this piece of rough. If the stone is “dark” then walk away. It doesn’t matter how pretty the stone is with back-lighting, you’re never going to see that color in a faceted stone.

Examine the color and quality of the light coming through. Look carefully for undesirable modifiers, and turn the stone about to see if different directions may show different colors. Consider dark directions and unwanted colors carefully – buy as a pessimist!

faceting rough aquamarine

Here are a pair of Aqua crystals. The one on the right shows reasonable color, while the one on the left is “sick” – both pale and green – neither of which are desirable in Aquamarine. Forgetting size, price for these crystals should be quite different.

facet rough garnet

A parcel of small red Garnet rough showing color and density. The brown modifier isn’t too bad, and the density is acceptable for commercial material. This parcel “passes” the white-paper test.

facet rough amethyst

This Amethyst crystal has much waste on the long, tapered end, but it has very nice color in the thicker area. It’s so dark we were concerned, but the white-paper test shows that good color will show after faceting. This stone is a winner!

amethyst facet rough

Although this Amethyst crystal is “pretty”, the strong zoning will present a graduated intensity of color when the crystal is cut into a single long gem. An evenly-colored crystal (and resulting gem) of this size and shape will be much more rare than this obviously zoned one – thus worth more.

CAUTION: Some Internet dealers show only white-paper photos, which is very good for determining color and density (60% or more of stone value), but poor for showing clarity. A photo from one direction also does not show color direction, which can be critical in gems like Tourmaline. When the only photo shown is a white-paper shot, you may wonder what’s going on with the clarity. Is the stone included?

CAUTION: Some Internet dealers show only back-lit photos, which is very helpful for examining clarity, but poor for showing color quality and saturation. When the only photo shown is a back-lit shot, you may wonder what’s going on with color density. Is the stone too dark?

CAUTION: Some Internet dealers place rough stones on white cardboard that has holes punched in it so they can back-light portions of the stones from beneath. Look carefully for rounded bright spots in photographs and you’ll discover the dealers who attempt to save time by combining into a single photo the two most useful lighting techniques for rough evaluation.


  1. Back-lighting is most useful for detecting inclusions and internal flaws. So, back-lighting a small portion of the stone discloses only a small portion of the stone’s clarity, and may not be representative of the entire piece.
  2. The whitepaper test is best for discerning post-cutting color saturation. So, pumping light in from behind a white-paper photo, even into a small area, may tend to artificially reduce the apparent saturation, making darker-than-optimal stones appear top-grade – and making too-dark-to-facet stones appear passable.

In fairness, photography is difficult, and time-consuming. And, the different lighting methods require different set-ups and camera settings. So, dealers tend to learn and use one photographic technique to present their wares. It is not my intent to insinuate dishonesty on the part of any dealer(s), but to alert the potential buyer to the inherent strengths and weaknesses of each presentation so they will know what to look for; what to ask for; and what to question before buying.

Look All Around (for flaws and inclusions, NOT color):

Focus on one thing at a time. If you’re surveying for flaws and inclusions then forget color – that’s a different job. Look through the stone from every direction. Use different lighting methods, and do a complete survey with each method before moving on to the other.

Side Lighting:

Hold the stone at the very edge of a light source so you can shade along the edge of an opaque shade or the edge of a flashlight. You can use a fiber-optic to direct light along thin paths and in specific directions. Side-lighting means left, right, top, or bottom – as long as the light comes into the stone from the side, and not toward you. Side-lighting usually causes inclusions to reflect light, so look for unexpected light spots in the stone.

flawed amethyst crystal

The side lighting (from the top) on this Amethyst crystal shows many internal flaws, two of which are marked with arrows. This stone is not suitable for cutting.

aquamarine with inclusion

Side lighting (top again) on this Beryl shows a storm of tiny bubbles within. Although this crystal, and internal features are quite beautiful, it is not suitable for cutting.

faceting rough aquamarine

Side lighting on this Aquamarine crystal shows flaws (yellow arrows), a cloud of bubbles (green arrow) and an icy frost-like layer, which is obviously opaque (blue arrow). Depending on the style of cutting and the orientation, this stone may be useful after the cloud and frost are sawn off.

aquamarine faceting rough

Note the many streaks within this Aquamarine. Features deep within the stone (and beneath the light) are reflecting light, and so are bright. Features that are closer to the camera are casting shadows, and so are dark. This stone will produce a “commercial-grade” gem.

“Candling” or back-lighting (for inclusions, NOT color):

Use varying intensities of back-lighting. You can also “pinch” the stone between fingers to shade light from glaring around the sides. Back-lighting usually causes inclusions to cast shadows, so when you’re candling look for dark spots.

facet rough tourmaline

This very-included Tourmaline is a good example of how inclusions cast shadows when back-lit. This stone is obviously unsuitable for cutting.

amethyst crystal specimen

This Amethyst specimen is not even transparent, and back-lighting shows this, and the internal growth patterns both very nicely. This is a “tumbler-grade” stone.

Water (for flaws and inclusions, NOT color):

Water can relieve much of the surface glare to let you see internal features – especially on shiny or “frosty” stones like Garnets or alluvial Topaz. Stick the stone in a glass of water and then use side lighting and back-lighting. Use your tweezers to turn the stone and remember to look in every direction.

faceting rough garnet

Water cuts the glare so the many inclusions in this Garnet are easily seen. This is not suitable for cutting.

faceting rough aquamarine

This beryl is in water, with back-lighting that shows off inclusions readily. One is marked – How many more can you find?

faceting rough aquamarine

This double view of the same stone shows how important it is to use different techniques and to look from different angles. Combining both techniques, notice how many flaws and inclusions are visible. This is a nice specimen, but unsuitable for cutting.

The following two stones are alluvial Topaz, with a very frosty surface. At first glance, there appears to be no way to discern whether these stones merit a second look.

facet rough topaz

…but watering and side-lighting easily show the serious problems with this stone, two of which are marked. Can you count the others?

topaz faceting rough in water

Likewise, the second stone has a very bad veil running through the middle. Neither of these stones is suitable for cutting a single large gem, but the second stone would readily produce a pair of gems after sawing away the veil.

You may have surmised that presenting goods on “white-paper” emphasizes the quality of color, while not showing clarity. Presenting goods under back-lit conditions emphasizes clarity, while overstating the brightness (understating color density). And, neither of these lighting methods accomplishes what side-lighting does.

Any reasonable gem rough evaluation demands one use all three techniques. Remember to use all three techniques whenever you examine a rough!

Determining what kinds of flaws and inclusions are acceptable is something for experienced experts. If you have doubts, send your stone for evaluation. Meantime, learning to see these features is an important step.


Following are a number of simple “case studies” showing a variety of evaluations made using the simple techniques above.

Amethyst, with flaws, inclusions, color-zoning, and growth-lines shown using watering.

facet rough amethyst

Other than some serious striped color-zoning this large Amethyst crystal looks acceptable with plain back-lighting.

amethyst faceting rough

But, using side-lighting and water, we can easily see a huge flaw trailing through the middle of the stone.

amethyst facet rough

The same stone, from different angles shows the severe color-zoning, and some very dark tendril-like inclusions, both of which would seriously degrade this stone’s appearance.

faceting rough amethyst

Watering is also fun just to enjoy the fascinating growth patterns!

Garnets with good color, and one stone with inclusions, demonstrating white-paper testing and watering.

garnet faceting rough

Here’s a parcel of red garnet, which I would reject from the beginning just based on size. There’s no way I can make money cutting these little stones, but a hobbyist could have many hours of enjoyment with such nice color. Notice how the white-paper test shows the color and color-density of the parcel. Larger stones of the same density would be too dark…

faceting rough garnet

Now that we’ve checked color and density, let’s change lighting and look for inclusions. Here’s back-lighting, and it looks like a few black inclusions.

faceting rough garnet

Now, the same stone back-lit and in water – notice how the inclusions show up!

Tourmaline, with flaw, shown using back-lighting and then white-paper lighting.

facet rough tourmaline

The classic back-lit photo shows the flaw in this stone – and what appears to be wonderful pink color. But, we know not to use back-lighting for color…

tourmaline faceting rough

The white-paper test reveals how dark this stone actually is – and an undesirable root-beer overtone, so this stone is rejected on two counts.

Smoky Quartz, showing color-density, clarity, inclusions, flaws – and demonstrating the white-paper test and watering.

faceting rough smoky quartz

This is what is meant by “glassy”!

faceting rough smoky quartz

The second crystal looks foggy, but much of that is surface-glare.

faceting rough smoky quartz

We use side-lighting and water to see the clarity of the upper portion; the inclusions in the base; and the bad flaw below the tongs. We can saw-away the flawed area and use the top!

Tourmaline Crystal, showing clarity, color, and C-axis and demonstrating white-paper lighting and back-lighting.

facet rough tourmaline

Back-lighting to search for inclusions, this Tourmaline “pencil” shows serious flaws near the ends, but a nice clean area in the middle. (The length-wise streak is on the surface of the stone.)

tourmaline faceting rough

The same crystal in white-paper test for color. Notice the lightest area along the bottom edge where light is reflecting off the crystal and coming back out. This stone will show a nice bluish-green color when cut.

tourmaline facet rough

The same crystal, looking end-on against very strong back-lighting shows that this stone has a closed C axis, which would be a problem in a short, blocky stone, but isn’t that troubling in a nice long pencil like this. We can still cut an acceptable gem from this rough.

We’ll need to subtract value for the closed C, and the wasted weight on both ends, but given the right price this crystal will be a winner.

Tourmaline showing flaws, inclusions, closed C axis and shape issues, and demonstrating white-paper lighting and back-lighting.

tourmaline faceting rough

When we candle this stone with back-lighting, we can clearly see a flaw appearing as a dark shadow.

tourmaline facet rough

Though the color looks great, the same flaw, deep in the center of the stone, is clearly visible due to the angle of the lighting. This stone would be rejected due to the flaw, but we want to complete the study just for practice…

facet rough tourmaline

Rolling the stone to test color from every direction, we see that the C axis is closed. Even without the flaw this stone would be a dud.

I hope you’ve found this lengthy page useful!

Please leave comments or questions below – or forward questions or suggestions, and I will be happy to answer (and upgrade the page).

Special Thanks to my colleague Jackson, for providing many of the Namibian gems pictured above, and for the questions that prompted me to create this page.

64 thoughts on “Rough Evaluation Class”

  1. Hello,
    I found this blog very helpful for evaluating the roughs. I am thankful to you for this blog and i wish i could meet you personally one day to have an advantage from your vast knowledge. I have qhestion regarding the luster of stone. Who do i check the rough that after cutting it will give good luster or not? Waiting for expert advice as it will be very helpful for me and others like me.

  2. It’s a very useful information. So, I realize that only few stone is the good stone. This is the different between expert and the ordanary.
    Thanks you

  3. You mentioned that the yellow-green C-axis color bleedthrough in tourmaline is undesirable, but I actually adore the effect in your example stone. How could I go about searching for that effect as a positive?

    Thank you for such a well-illustrated and thorough introduction to rough evaluation. I can’t wait to try my hand at faceting. Just picked up a small piece of topaz rough and Tucson, and I’ll keep your class in mind for next year!

    1. Hi, Michelle,

      If you are looking for that strong effect, you’ll just seek rough that displays it – and then cut to emphasize it rather than to conceal it.

      When you come to the live event we’ll show you how to do that.

  4. Thank you for publishing this article! My husband and I are learning to facet (mostly as a late in life hobby) and to find such clear and informative instructions are so very much appreciated. I just wish I would have started working in this field when I was young.

  5. Great information John ,
    I\’m new in this business with no experience, I have large amount of Rough Emerald ,I don\’t know how and where to sell it, should I cut or sell it rough which way is more profitable?

    1. Hi, Adam,

      Glad you find this page useful!

      > should I cut or sell it rough which way is more profitable?

      If there were one straight answer to that question, there would be no rough in the marketplace – or no polished goods. Profitability is a matter of your business model, your expertise, your network, and your business acumen.

      If you have no experience in the gem trade, the likelihood is very remote that you’ve made a purchase of a “large quantity of Emerald rough” that has much potential for profitability.

      Profitable deals are swept rapidly up by aggressive players who have experience, expertise – and strong networks on both buying and selling ends of their niche.

      I meet people almost literally every day with the idea they’re going to dive into this trade with no experience or network and make a fast buck right away – but I’ve never seen that happen. Success in this game generally occurs where technical expertise meets solid networking, business skills, and self-discipline.

      That said, I can’t advise anyone on any rough I haven’t seen.

      For information about consulting on your rough, consider having a look at these links:

  6. What will be the price for an emerald per carot from there are no price references to follow it becomes impossible to actualy estimate the price of rough.

    1. Vineet, prices for all gems vary greatly – and more in Emerald than perhaps any other. WHOLESALE Price for a 1-carat stone can be as low as $20 all the way up to $6,500. That’s 325 TIMES variation – and 60% or more of every step of that price range is based on the quality of the color (next comes clarity).

      The only way to estimate prices of rough are to know what that piece of rough will produce after cutting. The only way to learn this is with expert training and actual experience watching stones go from rough to finished. (I’ve never met someone who was good at rough pricing who wasn’t a competent cutter of stones.)

      It’s just not a simple thing, and there are no shortcuts for this learning process. EVERYONE I have seen trying to make a shortcut has lost their shirt.

      I hope this will help prevent you from losing yours!

  7. Whats the Green hexagonal crystal, I am only new to this and learning something new every day.

    Could it be from the Beryl family?

  8. As an older enthusiast rockhound, this is a welcome site with excellent information. I’m in Montana and am looking for sapphires and rubies, so this site is very interesting to me. Thank you for taking the time to share your knowledge.

  9. Hi! I picked up a raw uncut stone from Madagaskar a few years ago and thought nothing much about untill I saw a picture of a stone strickingly similair to the one I have and classified as one of the 10 rare gems in the world. It is called Grandidierite and seems to cost a fortune. The stone I have is a fairly large one (palm sized ) and I am wondering how to get it appraised. Can you help?

    1. Hi, Ashok,

      Appraising rough stones is a very tricky thing. Gemstones do not usually receive appraisal until after cutting (and setting). And, due to the nature of crystals, any valuation based on *potential* of being turned into a gemstone will be truly speculative. Thus, I doubt you will find someone who will “appraise” the stone for you, though you may find someone who is willing to render an opinion about the market for it.

      I am personally not expert in materials that are not transparent and suitable for faceting, so I can’t offer more assistance with this specific material. I recommend you seek out a specimen dealer or expert in non-transparent materials. And, I wish you great success with your acquisition.

  10. Hi John, I am new in the business, but have quite a large amounts of great gems. Over 100 kilos Sapphire with access to much more 5kg Flourite, Tourmalimes, Rhodolite, and a few bits and pieces here. I need to know what’s best in terms of making more money when it comes to selling. rough or cut and polished?

    1. Hi, Bruno,

      Welcome to the business, and congratulations on your huge acquisitions.

      “What is best” is dependent upon one’s experience, network, and the material in question. If you have a strong network in the specimen market and the material you have is specimen-grade, that’s where your best business will be. If you have a strong network in the polished goods market – including a strong network for having the goods polished – and the goods are also suitable to that use, then that’s your best strategy.

      Less-than-best outcomes happen when there are missing pieces, or mismatches between the suitability of the goods and the use one is trying to put them to. For instance, specimen-grade goods are worthless in the polished goods market, and polish-grade goods may draw less net profit if sold into the specimen market, etc.

      The newer you are in the business, the more conservative you should be – and the more you need expert assistance that is specifically related to the goods you have – or the network you are selling into. For instance, I would be of little to no help to you working in the specimen market or with opaque materials like Jasper or even with precious Opal – because those are not my areas of expertise or strong networking. If you have transparent facet-grade materials then I could help you evaluate, plan and perhaps even move them – because those are my areas of experience and work.

      So, look for an expert who can help you according to the kinds of materials you can get, to the network you intend to sell into. If I can help more, just ask!

  11. Thanks for the information it was useful for starters like us and it is highly competitive place for gems where I live in [Ceylon], so your information is very useful.

    Further, I hope that you would help me into judging the rough on faceting. Is there any way to know what type of gem it is, before faceting ?

    1. Hi, Naushid,

      Glad you’re finding the information useful.

      Rough evaluation is a complicated and challenging part of the business, and I’m unaware of anyone else teaching a systematic and comprehensive way to do that.

      Rough identification is one of the most challenging parts of rough evaluation. I recommend reading books on mineralogy and crystallography as well as those on gemstones. And, look at LOTS of rocks in person. Never miss a chance to look at gem materials. This is one of the most important things about going to shows – and as often as possible. Look at everything and compare everything. The people who are best at this skill are those who do that – looking, reading, staying curious all the time.

      You may have noticed this free on-line mini-course in gem rough evaluation:


      I invite you to check that out. If you come the the USA, perhaps you will consider attending one of our advanced Faceting Academy events – or catch our Rough Evaluation training in Tucson.

  12. Very good and informative blog John. I have been a keen rock-hound since childhood and have tended to drift toward specialising in sapphires here in Australia. For the people coming into the lapidary field your words are gold mate. I have met so many who were so excited from finding a “gemstone” rough and it nearly always brings them down to earth when I appraise their finds using exactly the processes you have expounded. I try to explain to them that top quality gems are few and far between and between them are a heck of a lot of stones that are best left in a display case as rough examples. I will be passing on the url for your excellent synopsis to people so they can apply the “rule of thumb” for themselves. Great work mate. Thank you.

  13. Hi John
    what is back & side-lighting ? and which is the best way to use torch light good for the job ? pls can you send some pictures for me .
    john can you recommend a optivisor to buy

  14. Hi John
    i’m from sri lanka
    i’m in this trade for one year but i couldn’t understand how to choose corundum rough stone for heat so john please help me
    this is the best web i see ever to study
    i follow a gemology class but i couldn’t understand this much it help me a lot
    Thank you

    1. Hi, Ahamed,

      Thanks for your note. I’m very happy that you find the site helpful – that is my goal. I would love to help you select corundum for heat treating, but heating is not my area of expertise. I have not studied it because it does not fascinate me the way designs, optics, and techniques do. So, my personal investment and journey are in those things. Thus, I cannot guide you about heating – or materials that are especially useful for heating. There are many resources on the Internet, though, and I wish you great success.

      Once you have gained expertise in heating, please return – as a resource for me and the others here.

      Best of luck in your hero’s journey!

  15. I have been searching for content related to rough gem stone for a long time , Finally I found this website which has a lot important information and extreamely helpful content for the people like me.There is an Emerald mine nearby my place and I want to gain more informantion about buying rough emerald. I bought some rough emeralds and got few of them cut already but I dont know how to grade the quality of these finish stones, I can send you the picture. If you can guide me through the correct path, It would be the great help. Thank you

    1. Hi, Kay,

      Glad you like the site and the rough class. Great that you’re having fun with the Emerald.

      It is not possible to do an appraisal of a gemstone with a photograph.

      It is also not possible to “guide someone” (teach appraisal) of precious stones in an e-mail or web page.

      If you are serious about pursuing that knowledge, I recommend you search for courses geared to teach appraisal skills and offer gemological certification programs. There are a couple of them that offer distance learning, combined with brief resident training and examinations. Reputable courses are neither short nor cheap – as the amount of learning involved is not trivial.

      Welcome to the world of gemstones!

      I hope this is helpful to you.

  16. John, thank you very much for the information. you have been extremely helpful. I did not realize you had written me back until I read your article and the replies everyone had written you, and then I came across mine that I had written. I think you will find it interesting that I know how to facet now. I met a someone who has faceted for nearly 30 years and she has taekn me in to learn the trade. I ended up cutting my daughter a ring (even though now I see I shouldn\’t have, its a marquise, and a pendant) I have cut nearly 20 stones to date and I am enjoying it very much. Again, I need to thank you. One question I have and I don\’t know if you can tell me, but I would like to know how to price different types of rough.

    OK, thanks again for everything


    1. Hi, Quentin,

      Nice to hear from you. And, Congratulations on learning to cut and completing 20 stones!

      You are on your way!

      “Evaluating” rough also means understanding what to pay – or not to pay – as well as how to get creative with what’s available to ADD VALUE to the material. Ultimately, that’s our job – ADDING VALUE to Nature’s first step.

      Even the beginner steps of that are WAY beyond a blog post or short video. At the Resident Academy we dedicate around 12 hours of hands-on study to that point – and that’s really just getting a healthy start.

      There are very few who are willing to teach rough evaluation – including the financial side of it – in any systematic way.

  17. very informative, thank you. my family and I are rockhound newbies and will be searching this site frequently to determine what we might be looking at

  18. This is a great website, thank God I stepped into it. I am a gemstone dealer from Tanzania, East Africa the country blessed with all kinds of gemstones including the unique Tanzanite only mined in Tanzania. I am looking for rough stone buyers such as amethyst,red garnet, green tourmaline, rodolite, citrine and others. Find us on facebook; Kasengo African Gemstones

  19. I came across you site and have been enjoying it all. My wife and I are new to rock hounding and have had lots of fun digging and finding gems. Our last trip to Franklin, NC I found a 9.5 carat saphire. I would love to make something for my wife but dont no where to start. Can I send you a picture for your opinion?

  20. Hi John
    I have a couple of aquamarines and tourmalines that I would like to send to you by email for your opinion.

  21. Very informative and i have to say Thank You! Well, I do have a question. I was in Southern Oregon and went Sun Stone hunting with my kids. We found a few stones and found out as we were leaveing the area that a few of them are facet material. I have some Champagne, some Schiller and some with a bit of red. One is for my daughter and the other I will have cut for my son. What can I expect to pay someone to cut these stones, then how much more to mount them. Which color should I have cut since I will only have maybe 3 done. It is very important to me as it is a sentimental gift for my kids as I rarely get to see them because of a divorce. Thanks again.

    1. Hi, Quintin,

      Glad you found the page useful!

      What a person pays for cutting services depends on the cutter.

      You can send stones to China or India and have them cut for around $2 per finished carat, plus shipping. That works great for low-grade stones where you don’t care about quality of cutting – or if they get stolen. And, you need to send a quantity. I did this for several years with my low-grade Sunstones – until the Chinese ripped me off for about $20,000 worth of rough…

      You can find a cheap-o cutter in the USA who isn’t a real professional, and who will cut stones for something like $35 each. The quality of such workmanship is usually on par with (or even below) what one gets from the Chinese. At least, you’re less likely to have your stones stolen, and you can send just one or two.

      You can find a professional cutter in the USA who will evaluate the rough critically and cut it with precision – possibly in an interesting design, but definitely with attention to maximizing beauty and value. Like most professional craftsmen in the industrialized world, such people will usually charge by the hour – at a rate comparable to any other very skilled craftsman who use expensive precision equipment and have years of experience and skill. So, between $50 and $150 per hour – for the amount of time required to do a good job with your irreplaceable raw materials. The required time is usually not less than 1.5 hours, and will range upward according to size and complexity of the job.

      My shop will fall into that last category.

      I hope this is helpful to understanding the vast range of “investment opportunities” that one may find for turning rough gem material into jewels.

      That leaves the question about setting the stones for wear. Sunstone is not appropriate for rings. It will invariably get ruined if worn much in a ring. So, we recommend pendants or earrings.

      The current price of Gold is a real issue in getting settings done, but small and simple commercial settings may be had for between a few and several hundred dollars, depending on size and complexity. And, the setting work is not significant in the scheme of things – seldom more than $50, tops.

      The price of an individual setting varies DAILY with the spot price of Gold. So, exact quotes are only good during business hours on the day they are given.

      I consult directly with any client wanting to assemble completed pieces like this, based on a detailed evaluation of the rough – and on the client’s goals and budget. Usually, we can design a program that will fit those things together to create some wonderful heirlooms. Contact me directly and we’ll evaluate your stones and your vision – and fit that into your budget.

      I hope this helps!

  22. I think I have found a gemstone in your site itself. Very informative for a beginner and
    very good education. Though I am in the autumn of my years, this is just fascinating. I may bother you with my finds, many from grewel heaps, also containing mini-nano chips of gold, perhaps also silver and of course mica. This is not a joke. I am enjoying every moment of it.

  23. laxmikant.rastogi


    I have a 28 carat rough Blue Sapphire from Kashmir. I am basically from India – Mumbai and somehow I have managed to purchase this sapphire though I have paid a price for it through my nose. I was recommended by an astrologer to wear a blue sapphire for astrological reasons this was about 6 months back however when I actually went to the root to find out how genuine the sapphires are in the local market I found out that most of the sapphires from Lankan are treated and Kashmir Sapphire ready to wear were very very expensive hence I thought the best would be to buy the rough. After lot of pain and arranging money I have managed to get in touch with a guy in Gujarat western part of India he had these roughs from a long time but not willing to part finally there was a commit to buy the entire lot he has about 819 carats in all ranging from 5 – 35 carats, this is where he sold me the sample on condition that once I cut this and find out the yield and color etc I will pay him his price per carat.

    Though Jaipur is considered as destination for cutting and polishing to gemstones I really dont trust this market since all possible frauds are committed in this market hence my search for a good cutter. Please let me know if I can send you pictures of rough sapphires and let me know if you can throw some light on this one. That being said I am willing to travel to your country I do have valid visa and open ticket.


  24. i have a 38ct rough emerald, even if it is poor quality i would like it to be cut into a stone or two for keep sakes and memories if possible. i don’t know much but i am learning a little at a time. like i said even if poor quality what could i expect?

    1. Hi, Alan,

      There are degrees of quality, and “poor” could mean anything from something that’s still jewelry-worthy – to something that won’t even hold together for the process. We can tell some things from photos of a rough, but can’t really definitively tell without the rough in the studio – to apply careful lighting from every direction, and perhaps some immersion oil, or even having to grind away some matrix.

      If you’re interested in having us evaluate the piece you have shoot me an e-mail with some good, in-focus photos as a start. If it looks promising, I’ll invite you to send it for personal evaluation.

      Hope this is helpful.

  25. perfect explanations and example’s. thank you very much.i would be pleaseful if u can explain about phenominal gem rough

    1. Hi, Razeem,

      Thank you for your comments.

      My focus is on transparent materials. So, I haven’t built the expertise in stones like Opal that would support me writing from a position of authority about it. Perhaps I’ll ask someone who is a true expert on Opals to do a guest page or post. I’ll think about this. Thank you for the suggestion.

  26. I find this website extremely interesting and full of helpful hints for a hobbyist trying to identify rough gem material. The part of testing a stone with white paper is fantastic.

    Thanks for the inspiration.

  27. What is the best way to get material from the native form (the rough rough) to the state you would generally consider facet ready? What method works best to remove the matrix and other native material without changing the shape of the crystal like tumbling does?

    1. Hi, L,

      Any preparation is going to change the shape of the rough. Preserving the crystal shape isn’t a consideration if you’re going to facet the stone. You just want to preserve the part you want to use. Mostly, this is done by sawing, though tumbling our even acid may be used.

      Hope this is useful.

  28. So great and useful info! thanks for sharing with us

    After reading, I have a question: does the inside flaw of aquamarine can be identified that it is natural or it is due to incoorect treatment?

    lookforward hearing from you

  29. This is an absolutely wonderful site and I am enjoying it very much.
    I do have one question, if the green tourmaline has a closed “c” axis and if it were not fractured, could the stone be cabbed into a stone with an asteration?

    1. Hi, Dan,

      In doubly-refractive material, light is broken into ordinary and extra-ordinary rays, polarized in different directions. Closed C is an optical effect due to the ordinary ray being completely absorbed.

      Asterated gems display an optical effect due to inclusions, tubes, or other structures oriented to the crystal structure of the gem and reflecting light – such as rutile in corundum which creates star sapphires.

      These are very different phenomenon – one a refusal to pass light and the other a reflection of light bouncing off an internal structure. So, no, a closed C won’t offer the opportunity to have a star or cats-eye gem.

      1. Thank you J.B., I think I understand. A close “c” axis is similar to a broken, damaged or twisted fiber optic line, which ends the transmission of light due to a fracture or refraction in the wrong dirrection.

  30. Thanks for the great info! I will be back for more! When you say closed c axis do you mean the stone comes to a point when viewed down the c axis?

    1. Hi, Greg,

      No, “closed C” doesn’t refer to a terminated or pointed crystal. It refers to crystal that will not allow light to travel through the C axis. Even if both ends of the stone are flat, and parallel to each other, no light will pass and the crystal will be black.

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  33. Stewart Ulberg

    Appreciate it for all your efforts that you have put in this. very interesting info . “The price of greatness is responsibility.” by Sir Winston Leonard Spenser Churchill.

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