Satin spar selenite mineral specimen from Badlands Petrified Gardens, Kadoka, South Dakota

Satin spar is a fibrous variety of gypsum (hydrated calcium sulfate) that forms in sedimentary environments through evaporation of mineral-rich waters. The Badlands region of South Dakota is renowned for producing high-quality selenite specimens, with the Badlands Petrified Gardens being a well-known commercial source that operated for decades selling specimens to tourists and collectors. This particular piece was mounted and labeled as a retail specimen, likely sold between the 1960s and 1990s when such tourist mineral specimens were extremely popular. Satin spar specimens appeal to mineral collectors, metaphysical enthusiasts, and geology educators for their distinctive silky luster and fibrous crystal structure. The Badlands Petrified Gardens label adds regional provenance and nostalgic value for collectors of vintage mineral specimens and South Dakota memorabilia. These specimens remain popular teaching tools for demonstrating gypsum's fibrous habit and are valued by collectors who appreciate documented locality specimens from historic commercial sources.