Cassiterite sentence example
The tin occurs in the form of cassiterite, and is found chiefly in or near the crystalline rocks, especially the granite.
The granite, which is intruded through the Eocene beds, is associated with a pegmatite containing tourmaline and cassiterite.
Of minerals containing this element mention may be made of cassiterite or tinstone, Sn02, tin pyrites, Cu 4 SnS 4 + (Fe,Zn) 2 SnS 4; the metal also occurs in some epidotes, and in company with columbium, tantalum and other metals.
Zirconia can be obtained crystalline, in a form isomorphous with cassiterite and rutile, by fusing the amorphous modification with borax, and dissolving out with sulphuric acid.
It is an amorphous white powder; but it may also be obtained in crystals isomorphous with cassiterite by heating the amorphous form with borax to a very high temperature.Advertisement
It occurs in metalliferous veins, often in association with iron-pyrites, chalybite, blende, &c., and in Cornwall and Devon, where it is abundant, with cassiterite.
Alluvial tin mining is carried on successfully in the neighbourhood of Embadaan, cassiterite to the value of £46,000 being exported in 1905-1907.
Mining for alluvial cassiterite continued right up to the 20th century but was at its maximum in the middle ages.
Placer cassiterite is free of deleterious minerals and is easy to recover having a high specific gravity.
Rutile assumes tetragonal forms isomorphous with cassiterite, SnO 2 (and also zircon, ZrSiO 4); anatase is also tetragonal, and brookite or thorhombic. Rutile is the most stable and anatase the least, a character reflected in the decrease in density from rutile (4.2) and brookite (4.0) to anatase (3.9).Advertisement