The Elements of Blowpipe Analysis

by Frederick Hutton Getman

Ores of Tin

Cassiterite, SnO₂, Sn . 79, O . 21.—

H = 6.0-7.0, G = 6.8-7.0.

Color, brown, black. Lustre, adamantine, brilliant. Occurs crystallized in square prisms. Reëntrant angles characteristic. Before the Bp. on Ch. with Na₂CO₃ and KCN reduced to a metallic globule of tin. In the borax bead gives characteristic reaction.

Stannite, 2 Cu₂S . SnS₂ + 2 (FeS . ZnS) Sn . S₂.—H = 4.0, G = 4.3-4.5. Color, steel-gray to iron-black. Lustre, metallic. Occurs usually massive and disseminated. Heated in an ignition tube it yields sulphur dioxide. Before the Bp. on Ch. it emits sulphur dioxide and becomes covered with oxide of tin. Before the Bp. on Ch. with Na₂CO₃ and KCN it gives an impure globule of copper. A very difficult mineral to determine.