Pentagonite (very rare)

Item Description

Pentagonite is one of those species that nearly everybody knows, but it really only found in one place in the world in any quantity. Interestingly, although virtually every specimen of Pentagonite you'll see on the market is from India, the type locality is the Owyhee Dam in Oregon. The species gets its name from the five-fold habit shape of the twinned crystals. The mineral is commonly found with Cavansite because the species are dimorphous (sharing the shame chemistry, but having different crystal forms). It has been suggested that Cavansite is a low-temperature form, and Pentagonite a high-temperature form of their respective species. Pentagonite gets its name due to the fact that the crystals form in unusual five-fold "pentagonal star" cyclic twins consisting of 5 individual crystals that loop creating a minor distortion of the crystal lattice. These 5-sided or 5-pointed crystals are incredibly rare in nature. For reference, here is a link to a photo of a close-up of a textbook twin of the material (https://www.le-comptoir-geologique.com/_media/img/small/pic7370.tmp.jpg). This small cabinet specimen features a good quality, 1.1 cm beautiful, sharp, neon blue aggregate of Pentagonite sitting on bladed beige Heulandite on basalt matrix. I feel these Pentagonites are not appreciated enough due to the fact they are still available on the market, but like many minerals from India, they are the finest representation of their respective species ever found. Keep in mind that minerals like Adamite from the Ojuela Mine or Fluorites from Southern Illinois, were undervalued back in the day due to their abundance, but have increased dramatically in value now that no more are being found.