Here is what is being offered in Tanzanite today.

	CERTIFIED NATURAL ZIOSITE (TANZANITE) 0.95 CTS SG103 Gem Traders	190.00	-	yes	-	13 hours 18 minutes
	CERT NATURAL ZIOSITE (TANZANITE) STONE 1.39 CTS SG 1933 Gem Traders	178.80	-	yes	-	13 hours 28 minutes
	DANASGEMSTONES	18.00	-	yes	5×3	1 day 9 hours
	Certified Tanzanite Round,.32 Carat DANASGEMSTONES	25.00	-	yes	-	1 day 10 hours
	CERTIFED TANZANITE STONE 0.60 CTS [C35] sedagems	79.99	-	yes	-	1 day 12 hours
	CERT NATURAL ZIOSITE (TANZANITE) STONE 1.66 CTS SG 1934 Gem Traders	208.05	-	yes	-	1 day 13 hours
	CERTIFIED NATURAL ZIOSITE (TANZANITE) 0.92 CTS SG104 Gem Traders	195.00	-	yes	-	3 days 10 hours

Mining Tanzanite

Caring for Tanzanite

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.

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).

Take the diamond industry.

If you want to read just the dry news of the industry itself, check out http://www.diamonds.net/news/, which contains links to such press releases as:

A website that has much more interesting articles is:
http://www.diamondne.ws/
with such articles as:

For collectors of rocks and gems (I”ll get to jewelry enthusiasts in a different entry!) there are such magazines as:

Rock & Gem (rockhounds.com/ which has joined forces with Rock & Gem.

Gems & Gemstones (www.gia.edu/research-resources/gems-gemology/index.html is a print magazine for the professional gemologist, and is priced accordingly.

The Mineralogical Record (www.minrec.org/ is “the mineral collector’s knowledge base.)

Rock and Minerals (rocksandminerals.org/): “Amateurs as well as professional scientists delight in and pore over Rocks & Minerals, which has published feature articles on mineralogy, geology, and paleontology since 1926. Regular departments explore such topics as minerals for the collector; microminerals; recent books, videos, and DVDs; coming events; museum news; and personalities in the field. Detailed lists of collecting opportunities in specific localities are published periodically, as are special theme issues. Spectacular color photographs appear throughout each issue.”

This alloy is called sterling silver. It consists of 92.5% by weight of silver and 7.5% by weight of other metals, usually copper.

Manufacturers are always experimenting with other metals toreplace the copper, in order to improve various properties such as reducing casting porosity, eliminating firescale, and increasing resistance to tarnish.

The metals they experiment with include germanium, zinc and platinum, as well as a variety of other additives, including silicon and boron.

However, no one alloy has emerged to replace copper as the industry standard, and alloy development is a very active area.

What is firescale?

When sterling silver is heated in air for processes such as soldering and annealing, oxygen reacts with copper in the alloy to form a dark coloured copper oxide known as ‘firescale’. At elevated temperatures, silver absorbs oxygen: this enables copper to oxidise below the surface of sterling silver, thus causing firescale to penetrate deep into the alloy.

This sterling silver watch had originally been silver plated to hide the firescale. The dark stain is, however, clearly revealed where the plating has worn away.

Firescale is removed or disguised by various processes. These processes add extra labour costs and often incorportate the use of harsh chemicals, e.g. cyanide.