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Slate is a fine-grained, foliated, homogeneous, metamorphic rock derived from an original shale-type sedimentary rock composed of clay or volcanic ash through low-grade, regional metamorphism. It is the finest-grained foliated metamorphic rock. [ 1 ]
Phyllite Banded gneiss with a dike of granite orthogneiss Marble Quartzite Manhattan Schist, from Southeastern New York Slate. Anthracite – Hard, compact variety of coal; Amphibolite – Metamorphic rock type; Blueschist – Type of metavolcanic rock; Cataclasite – Rock found at geological faults – A rock formed by faulting
In geology, rock (or stone) ... Petrology is the study of the character and origin of rocks. Mineralogy is the study of the mineral components that create rocks.
The stone’s origin could be anywhere between “Orkney and Shetland, down through parts of Caithness and Sutherland, down to Inverness, and then eastwards across to Aberdeenshire,” Bevins said.
Conglomerate (/ k ən ˈ ɡ l ɒ m ər ɪ t /) is a sedimentary rock made up of rounded gravel-sized pieces of rock surrounded by finer-grained sediments (such as sand, silt, or clay). The larger fragments within conglomerate are called clasts, while the finer sediment surrounding the clasts is called the matrix.
Slate was freed from the rockface by blasting in shot holes hammered (and later drilled) into the rock. Slate mines were usually worked in chambers which followed the slate vein, connected via a series of horizontal "Floors" (or "Levels"). The chambers varied in size between mines and were divided by "pillars" or walls which supported the roof.
The world's biggest consumer of slate is France, followed by the UK, USA and Germany. In 2012, Spain produced more than 580,000 tonnes (570,000 long tons; 640,000 short tons) of slate worth about $380 million. This made it the largest slate producer in the world, followed by China and Brazil. [3]
Astrophysicists classify this as a fourth type of rock: Primitive rock. [1] Primitive rocks "have never been heated much, although some of their constituents may have been quite hot early in the history of our Solar System. Primitive rocks are common on the surfaces of many asteroids, and the majority of meteorites are primitive rocks." [1]: 145