Turquoise, blues and greens
to temperature: above 250 degrees C, a loss of water
leads to a dull green color
Well known deposits occur in Persia, Sinai Peninsula, China,
Chile, Egypt, Turkey, Mesoamerica (Arizona).
is a hydrous copper aluminum silicate, that occurs in microcrystalline
nodules. Today, most turquoise has been "color stabilized",
meaning it has been impregnated with wax, plastic resins,
or sodium silicate, often with dye added. The use of turquoise
dates back to 3000 B.C.- 4000 B.C.in the Sinai. It was the
primary holy stone for Native Americans living in the Southwestern
United States. Every Navajo carried a "personal"
piece of turquoise. Middle Eastern tradition claimed that
turquoise prevented accidents, especially falling. It was
a talisman for horsemen, to keep them from falling off the
horse. This belief carried over to Europe, evolving into
the belief that if one did fall, no bones would be broken.
Médaillon, Tibet, turquoises, lapis-lazuli et pâte de verre. Musée Guimet, Paris.