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Monolith with bull, fox, and crane in low relief at Göbekli Tepe. The density of most stone is between 2 and 3 tons per cubic meter. Basalt weighs about 2.8 to 3.0 tons per cubic meter; granite averages about 2.75 metric tons per cubic meter; limestone, 2.7 metric tons per cubic meter; sandstone or marble, 2.5 tons per cubic meter.
Limestone often contains larger crystals of calcite, ranging in size from 0.02 to 0.1 mm (0.79 to 3.94 mils), that are described as sparry calcite or sparite. Sparite is distinguished from micrite by a grain size of over 20 μm (0.79 mils) and because sparite stands out under a hand lens or in thin section as white or transparent crystals.
Shelly limestone – Limestone containing many fossils; Travertine – Form of limestone deposited by mineral springs; Tufa – Porous limestone rock formed when carbonate minerals precipitate out of ambient temperature water
A lithographic limestone printing plate after use to print a map. Note the uniform fine texture of the stone. Lithographic limestone is hard limestone that is sufficiently fine-grained, homogeneous and defect free to be used for lithography. Geologists use the term "lithographic texture" to refer to a grain size under 1/250 mm. [1]
Robert J. Dunham published his classification system for limestone in 1962. [2] The original Dunham classification system was developed in order to provide convenient depositional-texture based class names that focus attention on the textural properties that are most significant for interpreting the depositional environment of the rocks.
The Unified Soil Classification System (USCS) is a soil classification system used in engineering and geology to describe the texture and grain size of a soil. The classification system can be applied to most unconsolidated materials, and is represented by a two-letter symbol. Each letter is described below (with the exception of Pt):
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About 7.9% of the crust by volume is composed of sedimentary rocks, with 82% of those being shales, while the remainder consists of 6% limestone and 12% sandstone and arkoses. [13] Sedimentary rocks often contain fossils.