Turquoise is a hydrated phosphate of copper and aluminium. Known by many names, the word "turquoise" is derived from the French "turques" for Turks, since the mineral was first brought to Europe from Turkey from the mines of Persia (now Iran). Found in a variety of colors, turquoise forms in a yellow-green shade if it contains Zinc, more of a green if Iron or Chrome is present, and the ever-desirable blue from the copper. The more intense the blue, the more copper there is in the specimen. In fact, turquoise is often mined with copper. While turquoise from Iran, China, Afghanistan, etc. is remarkable, we're going to focus on USA turquoise, where we get our turquoise to work with.
While mostly a coal mining community, Campbell County, Virginia also produced gorgeous specimens of turquoise. It's one of the few localities to have turquoise formed in micro crystals that give it a "glittery" look, as opposed to the smooth texture turquoise usually forms as.
Pre-historic tools have been found in the turquoise mines of California. In the past there were a several mines there, now it has slimmed down to a select few. In the late 1800's a company started mining here and their findings were marketed by The Himalaya Mining Company and the Toltec Gem Mining Company in NYC.
Arizona produces a large quantity of turquoise, known for being of great quality. The Sleeping Beauty mine (closed since 2012) for example, is known for their bright blue turquoise. From a mountain resembling a sleeping woman comes high-quality specimens known world-wide. It's known for it's true blue color and it's consistency.
Currently, Nevada produces the largest volume of turquoise in the USA. The Lone Mountain mine turquoise is second only to Lander Blue in value. With lovely spider web (the most popular from this mine, when the turquoise has matrix patterns resembling a spider's web) specimens as well as clear blue, Lone Mountain has also been a source of very rare "fossil turquoise". This is when plants and/or shells, often crinoid stems, have dissolved away and left just the turquoise. Lone Mountain turquoise is also known for holding it's color for decades. There are pieces of jewelry with Lone Mountain turquoise from the 1940's still with the rich blue hue from when it was first made.
Due to being soft and porous, turquoise has been treated throughout history. The Native Americans used to rub waxes and oils to not only darken the piece, but increase it's longevity. Also, they would attach a backing of a stronger material to make it more durable. Modern techniques are basically advances on the older processes. The Zackery Method is a proprietary blend created by James E. Zachery, an electrical engineer and active trader of turquoise. The specifics of the non-toxic brew are unknown to the public, but the solution is soaked into the turquoise and once done, is undetected unless the material is smashed and the parts are subjected to analysis.
The most common treatment for turquoise is "stabilizing", virtually all turquoise on the market has been treated in this way. This is when a material like epoxy is pressurized into the pores of the stone, leaving it much stronger and able to hold up to everyday wear. Since it absorbs into the pores, it doesn't have the appearance of being treated. Obviously, this process is much different from just using waxes and oils, but it also doesn't bloom like stones treated with waxes and oils do. Blooming is when the added material leaks out over time, creating a white deposit. While we like to be as natural as possible over here in the studio, we believe that making the most durable pieces to be of the utmost priority, that having jewelry last the longest is the best for the environment. We do not, however, use "Color Shot" stabilizing, where dye is added to the stabilizing material to get it closer to the the robin's egg blue we all love. All our turquoise is the natural color it was formed as.
Yet even further from what the Native Americans used to do, is "reconstituted" turquoise, which has been nicknamed "stove-top" turquoise. This is when little bits of turquoise that couldn't be sold as-is are crushed up and blended with a binding agent and poured into molds and dried. From there it is cut. While it is still turquoise-based the problem lays with it being sold as solid turquoise without informing the consumer of it being a composite.
Doublets are when a stone is too slim on it's own so it's glued to a stone or other material for more substance. This takes it's cue from when the Native Americans would make backings for their turquoise.
Sadly, the last category isn't turquoise at all, but "block turquoise". This is completely synthetic. Again, this would not be a problem as long as the consumer was informed, but often this is not the case. Since turquoise has been mined for so long (and therefore the resources are dwindling) and is one of the most popular gems, suppliers resort to tricks to try to sell synthetic stones as real. We avoid this problem by buying straight from the miners as well as purchasing it rough so we are able to tell by the structure that it is real as well as not dyed.
This is just a little drop in the bucket as far as the story of turquoise, which has a very long history (turquoise has been found in tombs circa 3000 BC). For now here's The Golden Mask of Tutanchamun, which is made of solid gold, inlay lapis lazuli, carnelian, turquoise, quartz, obsidian, and colored glass: