Chalk is a soft, white, porous, sedimentary carbonate rock. It is a form of limestone composed of the mineral calcite and originally formed under the sea by the accumulation and lithification of hard parts …

May 9, 2019 · Chalk is a soft, white sedimentary rock formed from marine microfossils. Learn its formation, mineral composition, properties, famous deposits, and uses.

chalk, soft, fine-grained, easily pulverized, white-to-grayish variety of limestone. Chalk is composed of the shells of such minute marine organisms as foraminifera, coccoliths, and rhabdoliths. The purest …

Dec 4, 2016 · : a prepared form of chalk or a material resembling chalk especially when used (as for writing on blackboards) as a crayon

CHALK definition: 1. a type of soft white rock 2. a stick of this rock or a similar substance used for writing or…. Learn more.

Discover a wide range of high-quality soft chalk pastels in vibrant colors, including fluorescent options. Perfect for drawing, blending, layering, and more.

Chalk is used in making lime, cement, and fertilizers, and as a whitening pigment in ceramics, paints, and cosmetics. The chalk used in classrooms, however, is usually artificial and not natural.

Chalk is a biological limestone derived from the tiny calcium carbonate shells of foraminifera and the calcareous remains of marine algae. It is soft, friable, porous, permeable and usually white to light …

Definition of chalk noun in Oxford Advanced Learner's Dictionary. Meaning, pronunciation, picture, example sentences, grammar, usage notes, synonyms and more.

a piece of chalk or a substance like chalk, often coloured, used for writing and drawing on a blackboard