Tanzanite is a very popular gemstone that may be found in blue, purple and even some slate gray coloring. Tanzanite was first discovered in Tanzania, thus the name Tanzanite. Tanzanite is actually a zoisite and zoisite comes in yellow and green shades, which can be found in Tanzania and Kenya. Some people think Tanzanite looks a lot like sapphire. Tanzanite is used as the birthstone for December and is a 6 1/2 on the hardness scale.