Birthstones: December - Tanzanite

December is lucky enough to have multiple birthstones - we focus on two. This article is one of two for the month.



Made famous by Tiffany's in the late 1960s and 1970s with a large publicity campaign, Tanzanite soared to popularity practically overnight. With Tanzanite's deep velvety blues and violets, high clarity, and ability to be cut into large, faceted stones, it's obvious why it's loved by jewelry wearers and gem collectors alike. 

Shopping for Tanzanite

The most valuable tanzanites are deep blue, have high clarity, and show three distinct colors in it's three crystal directions (pleiochroism).

Most Tanzanite on the market today begins it's journey as brown Zoisite, which is then heat treated to produce the beautiful violet and blues Tanzanite is known for. When you're shopping for Tanzanite, you should assume it has been heat treated unless there is an accredited gemological laboratory (like GIA) certificate or report stating otherwise. The heat treatment is permanent and will not fade over time.

Tanzanite is best suited for pendants, necklaces, or earrings. It can be set into rings, but it should be noted that Tanzanite is not as durable as Sapphire. If you want a Tanzanite ring, consider a setting that protects the stone a bit more and wear it with care.

Tanzanite makes for a beautiful gift for anyone with a December birthday, or for people who love blue gemstones. Tanzanite is also the traditional gift of a 24th wedding anniversary. 

Caring for Tanzanite

Tanzanite can be cleaned with warm soapy water and a soft bristled toothbrush. I would never advise cleaning your tanzanite with a steamer or ultrasonic cleaner as it can damage the gemstone. 

Major Tanzanite Moments

Vintage Tiffany's Ad. 


Tiffany's Tanzanite Pendant.

Sarah Jessica Parker in 420+ carats of Tanzanite.