Turquoise is typically opaque and available as massive material that is commonly used for cabochons, beads and carvings. The name Turquoise is synonamous with the name of the color of the material. It is found in various shades of blue, blue-green and green. It may be a solid color or veined with black or brown matrix and referred to as Spiderweb Turquoise. Turquoise is commonly simulated by other materials, both natural and artificial, that are often difficult to tell from the real thing. Turquoise may also be treated to improve color. Turquoise is possibly to most popular non-transparentmineral in the jewelry trade. It has been in use as a valuable gem since at least 6000 BC when it was mined by early Egyptians. It has been used as a cultural, religious and ornamental gem by many cultures throughout history and is still very popular today.
There are many locations for good Turquoise specimens including Ma’dan, 45 km northwest of Neyshabur, Iran; Katonto, north of Kolwezi, Katanga Province, Congo (Shaba Province, Zaire); and Greenlee and Gila Counties, Arizona, USA.