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Robert Boyle
Hennig Brand
Georg Brandt
John Dalton
Antoine Lavoisier
Albertus Magnus
Joseph Priestley
Carl Wilhelm Scheele

History of Science and Technology Index

 

Some examples of minerals

Rutile

Rutile

Rutile is a mineral found in igneous and metamorphic rocks. It is composed primarily of titanium dioxide (TiO2) in association with other minerals such as quartz (SiO2), tourmaline (a complex silicate mineral), barite (BaSO4), hematite (Fe2O3) and other oxides and silicates.

 

Columbite

columbite

Columbite is a mineral found in igneous rocks. It is an ore of niobium (Fe2+Nb2O6). Also called tantalite when there is more tantalum present than niobium (tantalite (Fe, Mn) (Ta, Nb)2O6). Associated with iron, manganese and magnesium oxides.

 

Chalcopyrite

Chalcopyrite

Chalcopyrite is a copper iron sulfide mineral (CuFeS2) found in igneous, metamorphic and sedimentary rocks. It is associated with pyrite (FeS), tetrahedrite (Cu9Fe2+3Sb4S13), galena (PbS), Cobaltite (CoAsS) and sphalerite (ZnS).

 

Images adapted from Understanding Science No. 28 Second Edition

 

HISTORY OF SCIENCE AND TECHNOLOGY

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Rocks, Minerals and Ores

What is a rock?

Rocks are a mixture of minerals. There are three main types of rock.

rocks

Image adapted from Understanding Science No. 88 Second Edition

 

Igneous (from the Latin ignis, meaning fire) : These rocks were formed from a molten state and originated from magma, the semi-fluid material that exists just under the Earth's crust. Igneous rocks can be formed at the surface, for example lava from an erupting volcano, or in chambers under the surface, forming rocks such as granite.

Sedimentary: Rivers, lakes, oceans and glaciers all transport and deposit small pieces of weathered rock. Wind can also transport small pieces of weathered rock. Deposits of this kind, sand and mud for example, compressed over long periods of time, form sedimentary rocks of which shale is an example. Some sediments have organic origins. The inorganic shells and outer coverings of small invertebrates, such as snails and crustaceans, survived the death of the organism and collected on the sea bed. When these became compressed they formed limestone and chalk.

Metamorphic: Both igneous and sedimentary rocks can be metamorphosed (changed) if they are exposed to high temperatures and pressures. This can happen due to movements of the Earth's crust or pressure from magma pushing up from below. Such increases in pressure and temperature, over long periods of time, can change limestone into marble and shale into slate.

 

What is a mineral?

A mineral makes up part of a rock. It usually occurs as a solid in the form of crystals and had a definite chemical formula. Minerals are inorganic in origin. Some minerals are found in rocks as the native element, for example gold and silver, but most are found as compounds.

 

What is an ore?

An ore is any rock that contains enough of a given mineral to be commercially viable to extract.

Using cobalt ores as examples:

There are more than 100 minerals that contain cobalt compounds but only around 30 of these contain enough cobalt to classed as ores. The 4 main cobalt ores are

  • Cobaltite (CoAsS) - mineral containing cobalt, arsenic and sulfur. It occurs in rocks association with other minerals such as magnetite (Fe3O4) and chalcopyrite (CuFeS2).

  • Skutterudite (CoAs3) - mineral containing cobalt and arsenic. It occurs in rocks associated with other minerals such as native silver, native bismuth, cobaltite and niccolite (NiAs)

  • Smaltite (Co,Fe,Ni)As2 - mineral containing cobalt, iron, nickel and arsenic. It occurs in rocks associated with other minerals containing nickel, copper, silver and other cobalt ores.

  • Safflorite (Co,Fe)As2 - mineral containing cobalt, iron and arsenic. It occurs in rocks associated with silver and other arsenic ores.

 

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