Scientific Name: Variesty of Zoisite
Group: Silicates – sorosilicates
Chemical composition: Ca2Al3(SiO4)(Si2O7)O(OH)
Colors: Purple to blue
Hardness: 6.5
Formation: Crystals flattened in an acicular manner, may be fibrously curved
Principal Sources: Tanzania, specifically the foothills of Mount Kilimanjaro
Special Notes: Tanzanite is the blue/purple variety of the mineral zoisite which was discovered in Tanzania in 1967, near Mount Kilimanjaro. Tanzanite is noted for its remarkably strong trichroism, appearing alternately sapphire blue, violet and burgundy depending on crystal orientation. It can also appear differently when viewed under alternate lighting conditions. The blues appear more evident when subjected to fluorescent light and the violet hues can be seen readily when viewed under incandescent illumination.