quartzite

views updated May 08 2018

quartzite A metamorphic rock composed mainly of quartz and usually formed by the metamorphism of quartz sandstones. If deformation has accompanied metamorphism the individual quartz crystals are elongate and take on a preferred orientation, defining a planar or linear fabric within the rock. Unmetamorphosed sedimentary quartzites (sandstones with a quartz cement) are known as ‘orthoquartzites’ to distinguish them from metamorphic quartzites (metaquartzites).

quartzite

views updated May 23 2018

quartzite Metamorphic rock usually produced from sandstone, in which the quartz grains have recrystallized. Quartzite is a hard and massive rock. It is usually white, light grey, yellow or buff, but it can be coloured green, blue, purple, or black by various minerals.