A sample of white Phosphorus in the form of an extremely white 1cm cube sealed under argon in an ampoule embedded in acrylic. Purity is 99.95%. The element name, symbol and atomic number are engraved on the cube.  This rare allotrope of Phosphorus is almost never seen this pristine and white!  This sample must be kept in the dark to prevent yellowing.  Any light exposure will gradually yellow the sample over time.