A true rarity, and yet in size enough for any collector of both thumbnails or important species...with a bizarre but classic pyramidal form for the species, with good luster and glassy, modified corners, this is one of the largest I have seen over the years. In fact, the SIZE of the crystal is ridiculously large and is the biggest I have seen for sale in my memory (I had this one first about a decade ago!). It is a superb, museum-quality specimen of an unusual mineral so rare that most people have never seen one. These are found as floaters in salt dome formations down here in Texas and Louisiana (there are just ten localities worldwide, so far as I know, but these grow the biggest). As a bonus, this large crystal is fairly gemmy, too, when backlit!