Cinder
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2008-06-24T20:01:26Z
Skinnattittar
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{{otheruses}}
A '''cinder''' is a [[pyroclastic rock|pyroclastic]] material ([[lava]] or [[magma]]). Cinders are either intrusive [[igneous rock|igneous]] (magma cooled inside the earth) or extrusive igneous (lava cooled outside of the earth). Cinders are similar to [[pumice]], which has so many cavities and is such low-density that it can float on water. [[Pumice]] or cinders are used in [[soap]], [[xeriscaping]], [[mulch]], and [[rock garden]]s.
[[Image:Volcano q.jpg|thumb|300px|Volcanic eruptions such as this one can create cinders. ]]
==Characteristics==
The following [[Geology|geologic]] characteristics define a cinder:
*Uncemented
*Vitric
*Having bubble-like cavities, called [[vesicle (geology)|vesicles]]
*Measuring not less than 2.0 millimeters in at least one dimension
*Apparent [[specific gravity]] between 1.0 and 2.0
Typical cinders are red or black in color.
==Uses==
[[Image:Volcanic cinder.jpg|thumb|300px|Volcanic cinder at the [[Mount Cayley]] volcanic complex, British Columbia, Canada]]
Cinders have been used on track surfaces and roads to provide additional traction in winter conditions. Cinders are also popularly employed as inorganic mulch in [[xeriscaping]], because of excellent drainage properties and resistance to erosion. In this context, they are referred to frequently with the synonym "lava rock".
==Chemistry==
Cinder is composed of 80% Group 4A elements, 18% chalcogens, and less than 2% rare earth elements.
==See also==
* [[Cinder block]]
* [[Cinder cone]]
* [[Igneous rock]]
* [[Scoria]]
* [[Tephra]]
[[Category:Volcanology]]
[[es:Ceniza]]
[[ru:Гарь]]