Arsenic
As
atomic number
33
melting point
817°C

1. Roast the mineral fragment on a charcoal block; a white crystalline sublimate of As2O3 is produced accompanied by white toxic fumes that smell of garlic; the sublimate forms at some distance from the assay.

2. When heated in an open tube, a white sublimate of As2O3 is produced accompanied by copious white fumes that reek of garlic; when heated in a closed tube, a distinctive brilliant black mirror of metallic arsenic is formed..

3. When exposed to the reducing portion of the flame, arsenic imparts a violet color to the flame; (care must be taken not to use platinum forceps or tweezers when performing this test).

4. Pour a small amount of powdered mineral sample in a beaker containing hot nitric acid; a white insoluble precipitate will form which when heated in a closed tube produces a distinctive grayish-black mirror of metallic arsenic.