Mineral Species: Datolite and Prehnite

Chemical Formula: CaBSiO4(OH)

Chemical Name: Calcium Barium Silicate

Mineral Class: Nesosilicate

Mineral Notes: Datolite is a rare mineral ocurring in cavities in basaltic lavas, often in association with Zeolites. It may be confused with minerals like Prehnite, but the characteristic porcelain-like appearance is unmistakable and readily helps identification. It also gives a green flame test indicating the presence of Boron.

Description: Several intermixed crystals of pale-green Prehnite and dark-green Datolite. Whereas the Prehnite crystals have smooth, angled faces, the Datolite is more rounded and the surface of the crystals has a rather attractive frosting. A nice specimen of both mineral species.

Location: Prospect Park, New Jersey, USA.