slate, fine-grained rock rock, aggregation of solid matter composed of one or more of the minerals forming the earth's crust. The scientific study of rocks is called petrology. Rocks are commonly divided, according to their origin, into three major classes—igneous, sedimentary, and
..... Click the link for more information. formed when sedimentary rocks such as shale shale, sedimentary rock formed by the consolidation of mud or clay, having the property of splitting into thin layers parallel to its bedding planes. Shale tends to be fissile, i.e., it tends to split along planar surfaces between the layers of stratified rock.
..... Click the link for more information. are metamorphosed by great pressure. Slate splits into perfectly cleaved, broad thin layers; this characteristically regular and planar cleavage is called slaty cleavage. In the formation of slate, pressure causes the flaky minerals within the sedimentary rock, such as mica, clay, and chlorite, to be reoriented; the flat faces of the minerals lie at right angles to the source of the pressure, and the planes of easy cleavage are also at right angles to the source of the pressure. The rock is not necessarily compressed in the same direction as the sedimentary layers were originally laid down, and because the compression crumples and deforms the original sedimentary layers, the planes of slaty cleavage usually cut through the old bedding planes. Slate is intermediate in hardness between mica schists schist (shĭst), metamorphic rock having a foliated, or plated, structure called schistosity in which the component flaky minerals are
..... Click the link for more information. and shale; the better grades are used for roofing. Its characteristic color is gray-blue. Slate is mined in Maine, Vermont, Pennsylvania, Georgia, Lake Superior, and the Rocky Mts.

slate

Fine-grained, clayey metamorphic rock that splits readily into thin slabs that have great tensile strength and durability. Some other rocks that occur in thin beds are improperly called slate because they can be used for roofing and similar purposes. True slates generally split not along the bedding plane but along planes of cleavage that may intersect the bedding plane at high angles. Slates may be black, blue, purple, red, green, or gray. Slate may be marketed either as dimension slate, used mainly for electrical panels, laboratory tabletops, roofing, and flooring, or as crushed slate, used on composition roofing, in aggregates, and as a filler.

slate

a. a compact fine-grained metamorphic rock formed by the effects of heat and pressure on shale. It can be split into thin layers along natural cleavage planes and is used as a roofing and paving material

b. (as modifier): a slate tile

2. a dark grey colour, often with a purplish or bluish tinge

3. Chiefly US and Canadian a list of candidates in an election

4. Films

a. the reference information written on a clapperboard

b. Informal the clapperboard itself

slate (redirected from slated)

slate

slate
(redirected from slated)