 | Usually when buying tanzanite, an eye clean stone should always be sought. Eye-visible inclusions decrease the value of tanzanite, except in the very rare cat's eye tanzanite, which has desirable inclusions that cause chatoyancy (the cat's eye effect). It is thought less than one in a million tanzanites have chatoyancy, making it an extremely rare and collectible gemstone. |  |
 | Tanzanite was discovered in the Merelani district of Tanzania near Mount Kilimanjaro in 1967 and is a single source gem. Tanzanite has quickly established itself as one of the premier gemstones in the world. |  |
