Fraction (mineral)

Typical shell-like break in obsidian

The break is a property of minerals and rocks , which is exhibited when as a result of mechanical overloading - for example, shock or pressure - a mineral or rock sample (. Cf. →  handpiece ) falls apart along irregularly shaped surfaces.

The appearance of the fracture surfaces, which is often used as a determining criterion, is usually described using the following adjectives:

• shell-like - in amorphous materials and dense aggregates, resembles the imprint of a shell flap (e.g. flint , quartz , glass )
• uneven
• smooth
• fibrous
• hakig - predominantly in solid occurring metals , which viscous be deformed (eg. gold , silver , copper , platinum )
• splintery
• earthy - grainy, irregular fracture surface, similar to weakly solidified sand (e.g. clay minerals )

See also

Cleavage

Web links

• Hardness of minerals
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