Definition
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Etymology
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Other Categories
Chalk is a soft, white, powdery limestone consisting mainly of fossil shells of foraminifers
From old English cealc chalk, lime, plaster; pebble, from Greek khalix small pebble, in English transferred to the opaque, white, soft limestone
Fine Grained Rock, Opaque Rock
Taconite is a low-grade iron ore which belongs to sedimentary rock and containing about 27% iron and 51% silica
Western Australia, Minnesota
From the name of Taconic Mountains in New England
Durable Rock, Medium Hardness Rock
Coarse Grained Rock, Opaque Rock