Prehnite Green Onion Faceted Natural BeadsPrehnite is a calcium aluminium silicate hydroxide that belongs to the Phyllosilicate sub class of minerals. Its crystal system is orthorhombic. It usually occurs in massive, botryoidal, granular or stalactitic habits, but can also (rarely) form prismatic, pyramidal or tabular crystals. The colour is usually pale green and yellow green, but it can be bottle green, yellow, white, grey or colourless. Prehnite it translucent to transparent with a