Page 7 - Curriculum Visions Dynamic Book

Smithsonite
Zinc carbonate, also called smithsonite, is found most commonly in limestone areas in veins that also contain lead. Zinc carbonate probably originated as a hot solution of zinc sulphide which was precipitated on reacting with the calcium carbonate (limestone).
Zinc carbonate is an important source of zinc for the mining industry. The name smithsonite comes from a 19th century English chemist who was the first to discover zinc carbonate in limestone. The prestigious Smithsonian scientific institution in Washington DC is also named for him, as he left a legacy in his will for its foundation.
 The dark coloured crystalline material is sphalerite. The brassy cubes are pyrite (iron sulphide).
 Pieces of zinc.
crystal: a substance that has grown freely so that it can develop external faces. Compare with crystalline, where the atoms are not free to form individual crystals and amorphous where the atoms are arranged irregularly.
hydrothermal: a process in which hot water is involved. It is usually used in the context of rock formation because hot water and other fluids sent outwards from liquid magmas are important carriers of metals and the minerals that form gemstones.
magma: the molten rock that forms a balloon- shaped chamber in the rock below a volcano. It is fed by rock moving upwards from below the crust.
sulphide: a sulphur compound that contains no oxygen.
 Zinc is best seen in its true bluish-white colour on materials where it has been newly applied, such as these galvanised steel nails. Over time the zinc reacts with oxygen in the air to form a coating of zinc oxide, which is dark grey in colour.
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