This is a thin plate of the best yellow-green color from here, mostly transparent in fact, and with crystals of high luster. The piece just displays gorgeously since so much light comes through it. Why is it so thin? It grew against a tanzanite crystal! There is a clear contact face on the back of this plate, showing the surface planes of a tanzanite crystal, and to prove it a minute bit of thin blue tanzanite is still attached behind the thickest part of the crystallized hemisphere atop.