Tanzanite is one of the birthstones for December (the other December birthstones are turquoise and blue zircon). The tanzanite birthstone is often described as “velvety,” mostly because of its deep and saturated color, which ranges from a pure rich blue to violet. The Merelani Hills of northern Tanzania is the only place on earth where tanzanite is mined comercially. North of the mines tower the snow-covered slopes of Mount Kilimanjaro.
Most tanzanite begins as brownish zoisite that is heat treated to produce the blue to violet hues that characterize this December birthstones. The resulting color is permanent, and there are no additional durability concerns.
Tanzanite has a hardness of 6 to 7. It can abrades easily and is therefore recommended for earrings and pendants. Protect tanzanite from high temperatures and sudden temperature changes.