Jewelry Television produces brief (very brief) documentaries on a variety of precious gems and jewelriy. Check out these two on tanzanite.
Mining Tanzanite
Caring for Tanzanite
January 25, 2010
January 18, 2010
More information on turquoise
Turquoise is an opaque, bluish to greenish mineral. It is a hydrous phosphate of copper and aluminium. Turquoise is rare, and valuable in finer grades.
Turquoise has been valued as both a gem and ornamental stone for thousands of years. However, like most other opaque gems, turquoise has been devalued recently with the explosion of treatments, imitations, and synthetics onto the market. However, most people still value the real thing.
The name Turquoise was coined in the 16th century from the French language, either from the word for Turkish (Turquois) or dark-blue stone (pierre turquin). Turquoise is not found in Turkey, but was traded at Turkish bazaars to Venetian merchants who brought it to Europe.
Turquoise was among the very first gems to be mined by the ancients. Many historic sites have been depleted, but some are still worked — as small-scale, seasonal operations, owing to the limited scope and remoteness of the deposits. Most are worked by hand with little or no mechanization.
In the United States, turquoise is often recovered as a byproduct of large-scale copper mining operations.
Turquoise is found in Iran, Sinai Peninsula, and the southwest United States ( Arizona, California, Colorado, New Mexico and Nevada.
January 11, 2010
The uniqueness of Tanzanite
Tanzanite is a gem noted for its trichroism (tri meaning three, obviously). Depending on the orientation of the crystals, a single stone can appear sapphire blue, violet, and burgundy, depending on how it is held up to the light. However, this blue color does not come naturally. In its rough state, tanzanite is usually a reddish brown color, .and must be heat treated to bring out the blueness.
Tanzanite — the blue/purple variety of the mineral zoisite — was discovered in 1967 in the Meralani Hills, near the city of Arusha, in northern Tanzania. Tanzania was mined successfully by entrepreneurs for some time, until the mines were nationalized by the Tanzanian government in 1972.
In June 2003, the Tanzanian government introduced legislation banning the export of unprocessed tanzanite to India (like many gemstones, most tanzanite is cut in the city of Jaipur). The ban was explained as an attempt to spur development of local processing facilities, thereby boosting the economy of the country.
Tanzania also produces tsavorite, diamond and ruby.
The story of Tanzania is an interesting one. The country came into existence in 1964, when the countries of Tanganyika and Zanzibar united. (Zanzibar is an island off the mainland coast).