The most important antimony mineral of commerce is stibnite (antimonite, antimony glance, gray antimony, or antimony sulfide). Beginners practicing the following tests should use antimony sulfide. 1. Antimony can usually be detected by the dense, white fumes given off and the heavy, white coating formed near the mineral when it is heated on charcoal with the blowpipe. To make this test: Transfer to a flat stick of charcoal a little of the mineral to be tested for antimony. Use about the amount of powdered mineral that can be held on the tip of a knife blade or a piece of the mineral about as large as a grain of wheat. Heat the mineral in the oxidizing (bluish) flame of the blowpipe until the material is thoroughly fused. By this treatment, most antimony minerals give off dense, white . fumes which often continue to rise even after the heating has ceased. These fumes deposit as a dense, white sublimate (coating) on the charcoal near the mineral; the outer edges, where the coating is thin, appear bluish-white. The bluish-white coating of antimony must not be confused with those of lead or zinc which are very similar on the outer edges.