1 LB. Lot Smooth not Polished Prehnite Freeforms 100% Genuine Prehnite Origin: Mali Average Size: 1.00-2.25 in Prehnite is a calcium aluminum silicate mineral with the chemical formula Ca2Al(AlSi3O10)(OH)2. Limited Fe3+ can also substitute for aluminum in the structure. It usually grows in globular formations, botryoidal, and stalactites. The stone was named after Dutch Colonel Hendrick Von Prehn and was first discovered in Germany in 1789. Often prehnite is found growing alongside epidote and is usually opaque. Since this is a natural product, please allow for variance in shape, size, color, patterns, etc. Some pieces may be outside the average size range. Picture is an Example Only This listing is for one 1 LB. lot of Prehnite. Crystal River Gems Wholesale and Bulk Fast domestic and international shipping.