6.3 Minerals

A mineral is a chemical substance which is a naturally occurring solid that has not been made by animal, plant or any other type of organism.
1. common minerals are haematite, bauxite, galena, malachite, chalcopyrite, rutile, cassiterite, chromite, pentlandite and opal
2. some minerals are pure elements.eg. silver and gold.
3. native copper is found as pure copper. more commonly, copper is found as an ore. three copper ores are bornite, azurite and malachite.
Ores are rocks that contain valuable minerals like iron and copper
main properties of minerals are their: hardness, lustre, colour, streak colour, flame colour
in flame tests, minerals are first ground into powders or dissolved. some of the poweres or dissolved mineral is then put into a hot flame. the mineral glows an gives the flame a charecteristic colour that may then be used to identify the mineral.
hardness is assessed by comparing minerals using Mohs scale.
colour is very useful when prospecting for minerals. for example, gold shows up as a yellowish colour in rock and soil.
lustre is how shiny a mineral is. lustre is divided into many categories. examples are glassy, waxy, metallic, dull.
streak is the colour left behind when you try to scratch and unglazed white tile with the mineral.

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	Criado por Haneen Ahmed quase 5 anos atrás