Correctly used, 'selenite' describes clear, colorless gypsum. The term is grossly overused, sometimes not even in reference to gypsum! This specimen, however, clearly deserves the moniker: it is a gypsum cleavage slab, water-clear and nearly completely colorless save for some light brown iron hydroxide/oxide inclusions on the back face. Very nice condition. Previous dealer price of $60. An excellent example from this 2017 find which (to my knowledge) has not been repeated. Better in person than my historically lousy photos suggest.