A silicate mineral whose thin, strong fibers separate readily. Used in heat resistance. Known for causing terminal respiratory illness
A silicate mineral whose thin, strong fibers separate readily. Used in heat resistance. Known for causing terminal respiratory illness
A steel-gray and brittle metal. Symbol, As. Highly poisonous
A stage in coal formation when biochemical action is exhausted
A primitive milling process whereby ore is placed in a round, rock lined pit and milled by a series of blocks or crushers, suspended by beams radiating from the centre of the pit
The grinding of ore in a rotating cylinder using larger pieces of usually homogenous ore to grind down smaller pieces into finer grades
Sandstone with high feldspar content, usually coarse-grained and pink to red
A substance containing gold
A monatomic, inert, colourless gas. Symbol, Ar. Used in light bulbs and fluorescent tubes