Coesite - quartz altered by extreme pressure

Coesite is a high pressure polymorph of common quartz. The catch is, it can only be produced by subjecting the quartz to extremely high pressures, such as those produced in large meteorite impacts.

Apart from impacts, coesite occurs rarely, but naturally, in rocks that have reached the surface after having formed at depths of more than 62 miles in the Earth's crust.

This sample is from the Dora Maira Massif, Western Alps. It is 23 x 19 x 17mm and presented in a 1.25-inch hinged perky.