Emerald is the green member of the beryl
family. Traces of chromium and vanadium in
the crystalline structure are what produce the green color. These
gemstones were mined by the Egyptian Pharaohs as early as 3000 B.C.
and the ancient Incas and Aztecs of South America regarded them
as holy. Today, the best and most valued, stones come from Colombia.
Mohs hardness 7.5 - 8.
This is a technique used to add decorative color to metals. Made
up of a vitreous pigment of metallic oxide mixed with powdered glass,
it is fused to the surface of a metal like copper, bronze,
under very high temperatures. The colors and transparency of the
fused glass will depend on the metal oxides used and the temperature
during firing. Also, see cloisonné