Pentagonite (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. There are a few minerals that are directly tied to a single world locality. Pentagonite (and Cavansite) are known worldwide thanks to the fantastic specimens from Wagholi. If it were not for the pieces from this locality, I don't think many people would know about Pentagonite. 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 magnificent intense electric blue color is what draws the eye, but the superb crystallization makes them all the more enticing. When it comes to rarities, most of the time, crystals are small and nondescript. In the case of a species like Pentagonite, the crystals are large, beautiful and the only specimens of note come from one place in the world. 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://i.pinimg.com/236x/07/ed/60/07ed60470bade3918ceff313f2d8a9d4--image-search-amber.jpg). Pentagonite 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. This piece features an electric blue color group of crystal "sprays" of Pentagonite measuring 1.1 cm across sitting beautifully atop bladed silvery-white Heulandite on basalt matrix. Please note that the matrix has been sawn on the sides and the base. A small bit of damage can be seen on the Pentagonite group, but it's still a nice representation of this rare and classic material.