Rochelle salt is also known as potassium sodium tartrate is a white, crystalline powder, which is odorless, having a cool, saline taste. Soluble in water and has a density of 1.77. Melting point 70-80 degrees Celsius. Non-toxic. It's uses include - baking powders, silvering mirrors, medicine (catharitic), media for growing crystals, for the control of radio frequencies, and wherever piezoelectric crystals are used and component in Fehling's solution. Per USPS Publication 52, this material is not regulated , non-hazardous, can be legally shipped and is sold, packed, labeled and, shipped in compliance with their guidelines . Packaged in a HDPE screw-capped jar or high density polyethylene tub, with lid. Shipping .90.