A really sharp MATRIX tanzanite, undamaged, gemmy as heck, natural and unheated...what more could you want in a thumbnail? This is a very classy piece! MOST tanzanite thumbs you can get are rather the same old boring single, nice as they may be. THIS, however, has real character and stands out. It is a superb thumbnail without breaking the bank, of a generally expensive gem species. I cannot believe I got it so cheaply, and I like to think I am passing a deal on. The matrix is actually prehnite, but with a blue tint.