Slate

Slate is a metamorphic rock of argillaceous origin and defined as a layered stone which may be split into thicknesses ranging from 8 to 14 mm. These slates may have calcareous and siliceous base and are generally fine grained. They occur in various shades of grey steel grey and brownish ash colors. Slate consists of many minerals such as mica, clay, small amount of chlorite, hematite, and other minerals.

Slate is formed under the earth crust with the cooling and solidification of magma ,which contains various minerals such as clay, slit, mica and chlorite. Slate takes its present shape of flat sheet when pressure the of mountain-forming movements in the earth's crust, squeezes the minerals into parallel layers.

The surface of slate has a well developed mark of cleavage. Slate, which is a metamorphic-argillaceous rock can be split into thin layers along the plane of cleavages formed due to flattened and elongated minerals.

Slates have been used since ages as a building materials for its natural beauty, decorating versatility, softness and durability. Its natural colors, textures and other inherent qualities matches all the varied requirements of today's home. Slates are natural cleft material, which have host of utilities. It can be used for exterior, interior, roofing and for flagstones as it is weatherproof and long lasting. Slate is also used to trim the fronts and lobbies of buildings.

But before using slate, it should be checked that whether it is properly calibrated or not because un-calibrated slate is very difficult to install. If it is not calibrated then its thickness should be gauged. Gauged slate has natural cleft on one side and "grooves" on the other.

The slate should be properly calibrated or gauged for thickness. Un-calibrated slate is very difficult and time consuming to install, even for the most experienced installer. (Un-calibrated means that the slate has natural cleft on both sides of the stone, and the pieces can vary in thickness). Gauged slate has natural cleft on one side and "grooves" on the other. The pieces come boxed and are the same thickness. It's very similar to laying a ceramic tile. A professional installation includes sub- floor preparation, setting everything level with tightly spaced joints, grouting, cleaning and sealing.