Gems and Jewels by Egantx7

Question 11

In 2002, the American Gem Trade Association added a gemstone named for this nation to its list of December birthstones, marking the first change to the list in some 90 years. This nation is the only nation in which a particular form of blue zoisite is mined in four places that will likely see an end to mining in the next half century, despite only being discovered in in 1967. This gem ranges from deep blue to violet to burgundy. Identify this African nation which is the only current nation to lend its name to a birthstone.

Tanzania (tanzanite)