Gypsum, var. Selenite , Bastrop County, Texas
Gypsum, variety Selenite with "fishtail" habit Locality: Along Pin Oak Creek, Bastrop County, Texas Chemical Formula: CaSO4 * H2O Crystal System: Monoclinic Specimen size: 4.125 in x 2.25 in .75 in Specimen weight: 23 grams Shared by the Middleton Collection (AGMS).