Fun Facts About December's Birthstone Tanzanite

Tanzanite is a stunning purplish blue gemstone that comes from Tanzania. Here are ten fun facts about this rare gem:


  • Tanzanite is the official birthstone for December and the suggested gift for the 24th wedding anniversary.
  • Tanzanite is a rare gem variety of the mineral zoisite.
  • Tanzanite gems are found only deep in the foothills of Mount Kilimanjaro.
  • Tanzanite is about a thousand times rarer than diamonds, as it comes from a single, concentrated source in Tanzania.
  • When mined, Tanzanite gems a usually a deep red color, but when heated it turns into a rich violet-blue.
  • Rarely, gem-quality tanzanite stones will heat to a green primary hue, almost always accompanied by a blue or violet secondary hue.
  • It is estimated that only about 1% of tanzanite jewels are gem quality, meaning that most of the stones found in the market are either low quality or color enhanced.
  • Natural tanzanite varies in color from light yellow to deep violet.
  • On the Moh’s Scale of Hardness, Tanzanite has a hardness of 6.5-7 which means it is a fairly soft stone.
  • It’s estimated that at the current rate of mining, the available supply of naturally occurring tanzanite jewels will vanish within the next 25 years.
  • Due to decreasing supply, tanzanite's value has increased by 400% since 2012.
  • The biggest tanzanite in the world, The Mawenzi, is a single large crystal of 16,839 carats and weighing well over 3kg. The Mawenz is named after Kilimanjaro’s second-highest peak.
  • Tanzanite gems are a healing crystal with properties of balancing emotions/mental stability, enhancing creativity and attracting prosperity.