MATERIALS They are mica, quartz, chlorite, carbonaceous matter and small amounts of iron oxides.
CHARACTERISTICS It splits easily into broad, parallel and thin sheets. The split surfaces are smooth and shiny. Slates are harder and less crumbly than shale rock (see “shale”)
COLOURS Most slates are grey, bluish grey or black. Some are green, red, purple, tan or brown.
USES It’s split into slabs used in roofing, blackboards, electric panels and floor tile. Some slate is used in making sinks, vats, laboratory equipment, billiard table tops and wall veneers. Waste slate is ground finely and used as a filler in paints, linoleum and some plastics.
REFERENCES The Golden Home And High School Encyclopedia Volume 16