What is Slate?
[[File:SlateUSGOV.jpg|thumb|right|Blue slate]] [[File:Slate Macro 1.JPG|thumb|right|Grey-green slate (6 cm X 4 cm)]]'''Slate''' is a [[Metamorphic rock|metamorphic]] [[Rock (geology)|rock]]. It is formed from [[shale]] by being under pressure and moderate heat. Shale itself is formed from [[mud]]dy [[clay]], splits into thin plates. This characteristic splitting is carried over into slate. [[Schist]] is a rather similar type of metamorphic rock. == Uses == [[Roof]]ing slates are used in many countries, though [[ceramic]] [[tile]]s have gradually taken over. Heavier slates can be used for flooring (inside and outside). Slates are used for the [[cladding]] (surface skin) of buildings, and sometimes in [[Wales]] there are whole buildings of slate. [[Gravestone]]s and memorial plaques are another use. Thick slate is used for [[billiard]] tables and [[laboratory]] bench tops, where its resistance to temperature changes and [[chemical]]s is useful. Slate was used for [[blackboard]]s and writing tablets in schools. {{Rock type}} [[Category:Metamorphic rocks]]