Hi there, this is Canyon Cassidys of the Nevada Cassidys, my family originated the Stone Mountain Turquoise claim out in Lyon Co. Nevada.
The colors of turquoise-
For discussion I will use my own material.
Stone Mountain Turquoise happens to have a large variety of color…
Most of all varieties of “green turquoise”.
In common place, most people associate the word “turquoise” with the common color centered somewhere between blue and green. The uncommon wisdom here is that turquoise usually not this color. From our research it appears that there are only a handful of mines that commonly produced the typical shade associated with turquoise in large amounts. Persian, tibetan and chinese, sleeping beauty and so on. Even though these turquoise mines also produced amounts of greener turquoise over the years.
Many of the smaller mines out there produce “only some” of the color shade associated with turquoise you might find in inks, dies or colored pencils or pictures of the Bahamas etc.
For example, damale has a great deal of green because it is mixed with variscite to produce a strange creamy green color. The copper bond in those stones are not like that of turquoise and show shades of color that do not occur in turquoise. Most of the pure green turquoise has a hue that is actually brown. Variscite when blown up on a photo of projector screen will show almost fluorescent shade of yellow and/or lime green. These colors are created by a chemical bond that is nearly all copper. Turquoise is always a less dominated chemical mixture.
Thinking Green – Iron the universal bonder
At Stone Mountain the host rock has a huge amount of iron, which runs in veins and knobs throughout the deposit. So we find green turquoise veins following the iron all over the deposit in a very random spiderweb like pattern. This sort of coloration caused by the iron can span out over the hillside for a very large distance, usually encompassing the whole claimed area and going far beyond the turquoise veins.
Iron as it turns out is the “universal bonder”. Iron can and does pull nearly all minerals into a chemical bond. So any turquoise deposit that has a good amount of iron is likely to produce great varieties of color and/or green shades of turquoise.
This fall I went through Berkeley and displayed some turquoise to a few jewelers in town. One of the jewelers is a gemologist and as soon as I showed him the stones he immediately went into a dictation about how iron makes turquoise harder. And that the iron is responsible for the green color, and that when turquoise has a little more copper than iron in the bond it comes out on the blue side of the spectrum.
The colors of turquoise are always a reflection of the chemical reactions that took place in the very spot where the stone was extracted. One thing we notice at Stone Mountain Mine is that when following a turquoise vein the color of one vein can change drastically to a totally different shade in just a few inches then revert right back to it’s originally discovered shade. This shows us how the influences of iron are dominant. Where ever the iron is condensed you are likely to see some green chemical reactions that took place in the stones found there.
Here is a typical green turquoise stone from Stone Mountain Mine,
Lapidary Artist / Miner