
Tanzanite
Named
by Tiffany's for the gem's origin, tanzanite
is new to many jewelry buyers. Seldom does a beautiful and popular
gemstone enter the world market. But in 1967 miners in northern
Tanzania, Africa, discovered a deep periwinkle-blue zoisite, which
was practically an instant success. This gem is strongly trichroic.
As you view the jewel from different angles, the facets dance with
electric hues from purple to blue, careful cutting avoids the third grayish tone.
Most
heat treatments intensify hues and/or clarify
internal inclusions. Even though it is possible to find examples of natural-colored
tanzanite, the vast majority on the market is a result of heating
the greenish-brown zoisite. The treatment is permanent, leaving no visible
indication that the material has been heated.
Tanzanite
needs extra attention. Two characteristics affect its care. First,
because it is softer than
quartz,
the usual precautions apply. Protect tanzanite rings from being
scratched by other gems, metal, and stones. Facet edges easily
abrade. Second, tanzanite has internal cleavage planes that can part
if struck. It is also somewhat brittle like
emeralds. Although perfect for pins, earrings, and pendants,
tanzanite set in rings is vulnerable, so be gentle. Wash your
tanzanite only in warm soapy water and
do not use mechanical cleaners or chemicals. Dry with a soft cloth. ( Thank
you to Fred Ward's Gem Care. )