This Specimen has been sold.
2.7" Green Prehnite Crystal Cluster - Morocco
This is a specimen of green prehnite found in Morocco. The prehnite crystals formed in seemingly striated patterns, all bunched up next to each other with rectangular, "bowtie" crystal structures. The crystals are translucent and can be found on both sides of the specimen.
Prehnite is a calcium aluminum silicate with the chemical composition Ca2Al(AlSi3O10)(OH)2. It generally occurs as volcanic cavity infillings, and typically is a shade between yellow and green, however colorless and blue specimens are not unheard of.