To me it’s such a summery color. I guess on the right winter day you can have a turquoise sky brilliant against the snow and bare trees.
Turquoise supposedly gets its name from the middle French for Turkey, since the trade routes that first brought turquoise to Europe came through that country.
It’s an opaque stone with a texture somewhere between waxy and glassy. It takes polishing well but is relatively soft. (Mohs 5-6) The color can change with exposure to cosmetics, oil, sweat and detergents as well as bright light. Turquoise seems to be another of those stones that is popular for rings but probably shouldn’t be used for them! At least take them off before washing your hands.
Turquoise is a secondary mineral; it forms when acid solutions leech elements from other minerals. It doesn’t have a crystal shape, so tends to form clusters or nodules in veins and often grows with other copper related minerals. (For example, chrysocolla or malachite. Great color combinations.) The blue in turquoise comes from the copper, and the green hints from iron and chromium.
Turquoise is one of the most ancient gemstones; it has been mined for at least 5000 years. The mines in the Sinai were already worked out by 2000 BCE! (And people have been making imitations almost as long. The Egyptians had faience, a type of pottery glazed in a turquoise color.)
In the states we tend to associate turquoise with the Southwest. In a lot of places it’s a lucrative secondary to copper mining. Apparently the classic Southwestern silver and turquoise jewelry is a fairly modern phenomenon. Supposedly the concept was pushed by traders in the 1880s. Before then Native Americans used turquoise in solid beads, mosaics and carving rather than settings.
Some of the turquoise minded in the southwest is still gem quality (especially the Sleeping Beauty and Kingman mines), but a lot of it is treated to get it stable enough to use.
It’s kind of frustrating, because it is hard to tell if material sold has been dyed or stabilized with plastics or epoxy. On the plus side, it has also led more recently to a type of stabilizing/reconstituting that adds brass or copper veining through the stone. It doesn’t make any pretense at being natural and is a lot of fun to work with!
The best imitation is called Gilson turquoise. It has both uniform color and veined variants. The most common way to fake turquoise is to dye naturally white stones that possess similar textures (and veining patterns).
Value for turquoise seems to be very much in the eye of the beholder. Some hold out for the most turquoise of the turquoises with very uniform color-the best quality of this type comes from Iran and is the most desirable in the middle east and much western jewelry.
Others prefer the stone to have a cob webbing of matrix when the pattern and color is complimentary, emphasizing the richness of the color. This is the type generally preferred by artists in the Far East as well as by many Southwestern artists.
Oh, and apparently there’s a Turquoise Museum in Albuquerque, NM. Who Knew?