A darn near textbook perfect gypsum crystal, glassy and highly transparent (definitely deserves the 'selenite' moniker) with just a few inclusions. Highly transparent; the wad of mineral tack behind the specimen (for support during photography)  is clearly visible. Very rare for the locality; of the 304 Clay Center mineral photos hosted at Mindat, only one depicts gypsum (and it happens to be this very specimen!). Minor blemishes (as expected; gypsum is quite soft) but overall fine condition.