Fracture (mineralogy)

This article is about the terminology used to describe fracture surfaces. For fractures in rocks and minerals per se, see Fracture (geology)

In the field of mineralogy, fracture is a term used to describe the shape and texture of the surface formed when a mineral is broken. A fracture is any local separation or discontinuity plane in a Geologic formation, such as a joint or a fault that divides the rock into two or more Mineralogy is an Earth Science focused around the Chemistry, Crystal structure, and physical (including optical) properties of Minerals A mineral is a naturally occurring substance formed through geological processes that has a characteristic chemical composition a highly ordered atomic structure and specific Minerals often have a highly distinctive fracture, making it a principal feature used in their identification.

Fracture differs from cleavage in that that the latter involves clean splitting along the cleavage planes of the mineral's crystal structure, as opposed to more general breakage. Cleavage, in Geology and related disciplines describes the tendency of a Mineral or rock to break along preferred planes of weakness Cleavage, in Mineralogy, is the tendency of crystalline materials to split along definite planes creating smooth surfaces of which there are several named types All minerals exhibit fracture, but when very strong cleavage is present, it can be difficult to see.

1 Terminology
2 See also
3 References

Terminology

Conchoidal fracture

Obsidian

Conchoidal fracture is a curved breakage that resembles the concentric ripples of a mussel shell. Obsidian is a naturally occurring Glass formed as an extrusive Igneous rock. Conchoidal Fracture describes the way that Brittle materials break when they do not follow any natural planes of separation. The common name mussel is used for members of several different families of Clams or Bivalve Molluscs, from both saltwater and freshwater habitats It often occurs in amorphous or fine-grained minerals such as flint, opal or obsidian, but may also occur in crystalline minerals such as quartz. Flint (or flintstone) is a hard sedimentary Cryptocrystalline form of the Mineral Quartz, categorized as a variety of Chert OPAL ( Open Pool Australian Lightwater reactor) is a 20 megawatt pool-type nuclear research reactor that was officially opened in April 2007 Obsidian is a naturally occurring Glass formed as an extrusive Igneous rock. Quartz (from German) is the most abundant Mineral in the Earth 's Continental crust (although Feldspar is more common in Subconchoidal fracture is similar to conchoidal fracture, but not as curved.

Earthy fracture

Limonite

Earthy fracture is reminiscent of freshly broken soil. Limonite is an ore consisting in a mixture of hydrated Iron(III oxide-hydroxide of varying composition Soil, often typeset as SOiL, is a four piece rock band from Chicago Illinois United States founded by Shaun Glass Tom Schofield Tim King and Adam Zadel It is frequently seen in relatively soft, loosely bound minerals, such as limonite, kaolinite and aluminite. Limonite is an ore consisting in a mixture of hydrated Iron(III oxide-hydroxide of varying composition Kaolinite is a Clay mineral with the chemical composition Al 2 Si 2 O 5( OH)4 Aluminite is a hydrous Aluminium Sulfate mineral with formula Al2SO4(OH4·7(H2O

Hackly fracture

Native copper

Hackly fracture (also known as jagged fracture) is jagged, sharp and uneven. Copper, as native copper, is one of the few Metallic elements to occur in uncombined form as a natural Mineral, although most commonly occurs in It occurs when metals are torn, and so is often encountered in native metals such as copper and silver. A native metal is any of a number of Metals that can be found freely in nature Copper, as native copper, is one of the few Metallic elements to occur in uncombined form as a natural Mineral, although most commonly occurs in Silver (ˈsɪlvɚ is a Chemical element with the symbol " Ag " (argentum from the Ancient Greek: ἀργήντος - argēntos gen

Splintery fracture

Chrysotile

Splintery fracture comprises sharp elongated points. Chrysotile or white asbestos is the most commonly encountered form of Asbestos, accounting for approximately 95% of the asbestos in place in the United States It is particularly seen in fibrous minerals such as chrysotile, but may also occur in non-fibrous minerals such as kyanite. Chrysotile or white asbestos is the most commonly encountered form of Asbestos, accounting for approximately 95% of the asbestos in place in the United States Kyanite, whose name derives from the Greek word kyanos, meaning blue is a typically blue Silicate Mineral, commonly found in Aluminium -rich

Uneven fracture

Magnetite

Uneven fracture is self descriptive. Magnetite is not to be confused with Magnesite or Maghemite. Magnetite is a ferrimagnetic Mineral with chemical It occurs in a wide range of minerals including arsenopyrite, pyrite and magnetite. Arsenopyrite is an iron arsenic Sulfide (FeAsS It is a hard ( Mohs 5 Magnetite is not to be confused with Magnesite or Maghemite. Magnetite is a ferrimagnetic Mineral with chemical

References

Rudolf Duda and Lubos Rejl: Minerals of the World (Arch Cape Press, 1990)
http://www.galleries.com/minerals/property/fracture.htm

A fracture is the (local separation of an object or material into two or more pieces under the action of stress. A fracture is any local separation or discontinuity plane in a Geologic formation, such as a joint or a fault that divides the rock into two or more Conchoidal Fracture describes the way that Brittle materials break when they do not follow any natural planes of separation.

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