Physical properties of minerals:

• Cleavage describe the way a mineral may come apart or cleave in different ways. In thin sections, cleavage is visible as thin lines across a mineral.
• Color indicates the appearance of the mineral in reflected light (i.e. what it looks like to the naked eye).
• Diaphaneity refers to the degree to which a material transmits light.
• Fracture describes how a mineral breaks other than along natural cleavage planes.
• Hardness: the physical hardness of a mineral is usually measured according to the Mohs scale of mineral hardness.
• Luster indicates the way a mineral's surface interacts with light and can range from dull to glassy (vitreous).
• Morphology
• Specific Gravity: (or density) relates the mineral weight to the weight of an equal volume of water.
• Streak is the color of a crushed mineral's powder.

Other properties: fluorescence (response to ultraviolet light), magnetism, radioactivity, tenacity (response to mechanical induced changes of shape or form.)

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Chemical properties of minerals:

Minerals may be classified according to their chemical makeup and are listed below in approximate order of their abundance in the Earth's crust.

Silicates

The largest groups of minerals by far are the silicate. Some important rock-forming silicates include the feldspars, quartz, olivines, pyroxenes, garnets and micas.

Carbonates

The carbonates consist of those minerals containing the anion (CO₃)^2- and include calcite and aragonite (both calcium carbonate), dolomite (magnesium/calcium carbonate) and siderite (iron carbonate). Carbonates are commonly deposited in marine settings when the shells of dead planktonic life settle and accumulate on the sea floor. Carbonates are also found in evaporitic settings (e.g. the Great Salt Lake, Utah) and also in karst regions, where the dissolution and reprecipitation of carbonates leads to the formation of caves, stalactites and stalagmites.

Sulfates

Sulfates all contain the sulfate cation, in the form SO₄. Sulfates commonly form in evaporitic settings where highly saline waters slowly evaporate, allowing the formation of both sulfates and halides (q.v.) at the water-sediment interface. Common sulfates include anhydrite (calcium sulfate) and gypsum (hydrated calcium sulfate).

Halides

The halides are the group of minerals forming the natural salts and include fluoride, common salt (known as halite) and sal ammoniac (ammonium chloride). Halides, like sulfates, are commonly found in evaporitic settings such as playa lakes and landlocked seas (e.g. the Red Sea).

Oxides

Oxides are extremely important in mining as they form the ores from which valuable metals can be extracted. They thus commonly occur as precipitates close to the Earth's surface. Common oxides include hematite (hydrated iron oxide = rust), spinel (magnesium aluminium oxide - a common component of the mantle) and ice (hydrogen oxide!).

Sulfides

Many sulfides are also economically important as metal ores. Common sulfides include chalcopyrite (copper iron sulfide) and galena (lead sulfide).

Phosphates

The phosphate group actually includes any mineral with a tetrahedral unit AO₄ where A can be phosphorus, antimony, arsenic or vanadium. By far the most common phosphate is apatite which is an important biological mineral found in teeth and bones of many animals.

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