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Slate

A fine-grained metamorphic rock that splits into thin, smooth-surfaced layers.It also means a piece of this rock cut for use as roofing or surfacing material or as a writing surface. A fine-grained metamorphic rock derived from clays and more often, shales. Slate has a cleavage that permits it to be readily split into thin, smooth sheets.

Any of the deformed fine-grained, mica-rich rocks that are derived primarily from mudstones and shales, containing a well-developed, penetrative foliation that is called slaty cleavage. Slaty cleavage is a secondary fabric element that forms under low-temperature conditions (less than 540°F or 300°C), and imparts to the rock a tendency to split along planes. It is a type of penetrative fabric; that is, the rock can be split into smaller and smaller pieces, down to the size of the individual grains. If there is an obvious spacing between fabric elements (practically, greater than 1 mm), the fabric is called spaced. Slates typically contain clay minerals (for example, smectite), muscovite/illite, chlorite, quartz, and a variety of accessory phases (such as epidote or iron oxides). Under increasing temperature conditions, slate grades into phyllite and schist.

Material Notes:
Low metamorphic rock; the parent of most slates are clay or shale. Critical minerals are quartz (5-40%) and mica.

Floorings
A large variety of colors in slate stones are used for flooring purposes. Different colors in slate include browns, greens and purples, sea greens and grays.

Roofing
Slate stone is used extensively for roofing both commercial buildings and residences. Natural slate stone, being weather proof, highly durable, and attractive is an ideal medium for roofing.

Paving
For all kinds of paving application(specially exterior), slate is the perfect choice. Availability in a wide range of colors - shade or combination of gray, green, purple, black and red, makes it the topmost medium in the priority list.

Wall Cladding
Yet another area of application of slate stone is wall cladding. Slate stone is highly used for wall cladding as it is resistant to all kinds of weather changes and environmental conditions.

Landscaping
Natural Slate stone is also gaining popularity as a stone for lanscaping owing to its innate rugged and soft texture.

See also: Phyllite; Schist; Shale.

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