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
Jasperoid is a rare, peculiar type of metasomatic alteration of rocks
From silica, the main mineral content of Jasperoid
Durable Rock, Medium Hardness Rock
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock