Sunstone Discovered in Mexico
One of the more exciting developments in the mining game this year is the discovery of a new Sunstone deposit in Mexico.
Located by Ruben Valenzuela in the State of Sinaloa, this new copper-bearing Sunstone from the Aztecsun mine shows both similarities and differences to the material from Oregon.
In the numerous specimens that I’ve tested, the Refractive Index seems to average about 0.01 less than the Oregon material.
The crystal structure is certainly triclinic, as shown in the beautiful large specimen-on-matrix below.
The external surfaces of most roughs display the typical features of gem Feldspar, including the telltale signs of transformational twinning.
Some of the crystals found here are quite large, as shown by this specimen on matrix.
The new discovery is very unique because it contains copper schiller, much like that found in Oregon stones, and so far in a pattern that we would describe as “snow-flake schiller”, for the relatively even distribution within the stones.
This photo shows copper schiller in a faceted stone.
This oval faceted stone weighing 10.45 carats shows copper schiller that is very similar in appearance and beauty to the Sunstone from Oregon.
This rough, weighing 80.5 carats, shows a nice copper schiller,
and will be great for carving.
Another very exciting feature of the Mexican find is the average size of the stones. This rough weighs 275 carats – and we have reports of stones as big as 550 carats.
Larger-size stones are being produced in quantity at the Aztecsun,
as shown in this photograph of recent production.
Something else that I’ve never seen in gem feldspar is the beautiful smoky-quartz color, shown here in a 50.6-carat specimen. This coloration is appearing in a significant percentage of the material from production.
Adding to the unique characteristics of the material from Aztecsun mine are hollow tube-like voids within many of the crystals. We’ve seen these kinds of intrusions in the Oregon material, but usually more seldom, and usually isolated or in small numbers.
However, some pieces from the new find are completely shot-through with these fascinating features that vary in size from almost hair-like to over a millimeter in diameter.
This 26.6-carat native-cut specimen displays the smoky color quite nicely – along with some of the black inclusions that appear to be more common in the new find than in the Oregon material.
One of the most exciting features of the Aztecsun material is the size and availability of coveted “silver schiller” effect stones. We find some material exhibiting this appearance in Oregon, but they are usually smaller, less intense, and quite rare.
This 13.5-carat native-cut gem was fashioned from a rough that looked similar to the one immediately above. The shimmering effect is very silver with a blue tint.
A few pieces of this material have been found with such intense
shimmering features that they seem to glow with thier own light.
This is the cabochon cut from that rough, but it seems impossible
to get a photo that does it justice. The thing just glows from all around.
There are two additional minerals being recovered from the
Aztecsun, including this as-yet unidentified intense green gemstone.
The other as-yet unknown mineral is a grey metallic substance that forms in pretty octahedrals, most of which display some melting. The surfaces of many
of these pieces display an iridescent sheen.