Osmium Tetroxide crystals OsO4 Reagent Grade 1 gram.
Oxidizer for visualizing cells in microscopy.
Forensics Lab Supply Number 0027681.
MSDS: http://www.jtbaker.com/msds/englishhtml/o5704.htm .
This item is available only to established research facilities. It is a particularly nasty chemical. It can only be handled by those who are expert in the field of both inorganic chemistry and microscopy.