Found, Lost, and Found Again: The Geological and Gemological Significance of the Salininha Emerald Deposit, Brazil

Gem-quality sapphires containing ‘exotic’ elements such as Sn, Nb, Zr, Ta, W, are of special int

Gemology is traditionally practiced in laboratories, focused on identifying and analyzing gemstones.

Most of the spinels are found in shades of red to purple. Colourless, green and cobalt bearing varie