Limestone Quarry, Minya, Egypt

The first geologist to distinguish limestone from dolomite was Belsazar Hacquet in 1778.
Description
Like most other sedimentary rocks, most limestone is composed of grains. Most grains in limestone are skeletal fragments of marine organisms such as coral or foraminifera. Other carbonate grains comprising limestones are ooids, peloids, intraclasts, and extraclasts. These organisms secrete shells made of aragonite or calcite, and leave these shells behind after the organisms die.