Name/Title
TanzaniteEntry/Object ID
2013.1.31Description
Chemical Composition: SiO2
Crystal System: Triclinic System
Description: Common Name: Tanzanite
Chemistry: (Ca2Al3(SiO4)(Si2O7)O(OH))
Group: Silicates
Location: Merelani Hills, Lelatema Mountains, Simanjiro District, Manyara Region, Tanzania
Description: This is a small specimen with a rough shape. It is a transparent blue with some white.
Physical Charateristics:
Tanzanite is the blue/purple variety of the mineral zoisite (a calcium aluminium hydroxy silicate) discovered in the Mererani Hills of Manyara Region in Northern Tanzania in 1967, near the city of Arusha and Mount Kilimanjaro. It is used as a gemstone. Tanzanite is noted for its remarkably strong trichroism, appearing alternately sapphire blue, violet and burgundy depending on crystal orientation.[1] Tanzanite 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. Tanzanite in its rough state is usually a reddish brown color. It requires artificial heat treatment to 600 °C in a gemological oven to bring out the blue violet of the stone.[2] Tanzanite is a rare gem.[3][4] It is found only in the foothills of Mount Kilimanjaro. The mineral was named by Tiffany & Co. after Tanzania, the country in which it was discovered. Because it is relatively soft, tanzanite is most commonly set in necklaces and earrings.[5]
Fracture: Conchoidal
Hardness: 8 Topaz
Luster: Glassy
Rock Type: Sedimentary
Specific Gravity: 2.68-2.72
Streak: WhiteCollection
RAGM Mineral CollectionDimensions
Width
1-1/8 inDepth
1-1/8 inLength
1-3/8 inLocation
Location
Display Case
FS-11Room
Frieda Smith HallBuilding
Crater Rock MuseumCategory
ExhibitMoved By
Ian C.Date
January 29, 2025Notes
Location/ inventoryLocation
Display Case
FS-4Room
Frieda Smith HallBuilding
Crater Rock MuseumCategory
PermanentDate
August 18, 2023
