Limestone Slate

Limestone

Limestone is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate CaCO3. Limestone forms when these minerals precipitate out of water containing dissolved calcium. This can take place through both biological and nonbiological processes, though biological processes, such as the accumulation of corals and shells in the sea, have likely been more important for the last 540 million years. Limestone often contains fossils which provide scientists with information on ancient environments and on the evolution of life.

Slate

Slate is a fine-grained, foliated, homogeneous, metamorphic rock derived from an original shale-type sedimentary rock composed of clay or volcanic ash through low-grade, regional metamorphism. It is the finest-grained foliated metamorphic rock. Foliation may not correspond to the original sedimentary layering, but instead is in planes perpendicular to the direction of metamorphic compression.

Slate gray

Slate gray is a moderate shade of gray with a slight azure tinge, which represents the average color of slate, a metamorphic rock often used in stonemasonry. As a tertiary color, slate is an equal mix of purple and green pigments.

limestone

Noun

1. An abundant rock of marine and freshwater sediments; primarily composed of calcite (CaCO3); and occurring in a variety of forms, both crystalline and amorphous.

slate

Noun

1. A flake or piece of certain types of stone that tend to cleave into thin layers.

Adjective

1. Having the bluish-grey colour of slate (noun etymology 1, noun sense 4).