Kuruman, South West Africa
Toenail, 3.1 x 1.9 x 1.7 cm

A GEMMY specimen of this rarity, which to my understanding is thought to be some kind of a mix or transition between ettringite and sturmanite (though I admit that I have heard conflicting accounts of this and some dealers DO consider it a valid species on its own merit). Either way, it is a very pretty specimen and shows crystals that are much more developed than the amorphous material you typically see. Old material, from the ettringite mining heyday of the 1980s and not to my knowledge found since