Cinder 1280085 221502500 2008-06-24T20:01:26Z Skinnattittar 2890936 {{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]]