Discovered only in 1967 in Tanzania, this lovely gem has been a worldwide success, and demand continues to exceed supply. Tanzanite is a variety of zoisite, which is a member of the epidote group. Colors range from blue to purple to green. The most highly coveted color is the deep blue which shows a purple hue shimmering around it.
Tanzanite is trichroic and exhibits pronounced pleochroism. The colors respective to the three vibrational directions are sapphire-blue, sage green, and purple. Orientation is an important consideration for cutters who need to consider both the yield and the resulting color.
About Sphalerite Sphalerite is a rare collector’s gem whose claim to fa...
About Obsidian Obsidian is a naturally occurring volcanic glass. It is formed...
About Zircon Zircon is known since the Middle Ages. The oldest known zircons ...
About Prehnite Prehnite, a form of calcium aluminum silicate, has a vitreous ...
About Golden Beryl Beryl (Beryllium Aluminum Silicate) is one of the most imp...
About Sapphire Sapphire, with its Mohs hardness of 9, second only to diamond,...