Cryptocrystalline is a rocktexture which is so finely crystalline, that is, made up of such minute crystals that its crystalline nature is only vaguely revealed even microscopically in thin section by transmitted polarized light. Among the sedimentary rocks, chert and flint are cryptocrystalline. Also a form of diamond, known as carbonado, is cryptocrystalline. Volcanic rocks, especially of the acidic type such as felsites and rhyolites, may have a cryptocrystalline groundmass as distinguished from pure obsidian (acidic) or tachylyte (basic), which are natural rock glasses. Rock redirects here. ... In materials science, texture is the distribution of crystallographic orientations of a sample. ... For other uses, see Crystal (disambiguation). ... Photomicrograph of a thin section of gabbro. ... This article treats polarization in electrodynamics. ... Two types of sedimentary rock: limey shale overlaid by limestone. ... Chert Chert (IPA: ) is a fine-grained silica-rich cryptocrystalline sedimentary rock that may contain small fossils. ... This article is about the sedimentary rock. ... Carbonado is a natural polycrystalline diamond found in alluvial deposits in the Central African Republic and Brazil. ... This article is about volcanoes in geology. ... For other uses, see Acid (disambiguation). ... Felsite is a very fine to cryptocrystalline igneous rock that may or may not contain larger crystals, called phenocrysts, that are typical of many porphyritic igneous rocks. ... This page is about a volcanic rock. ... The matrix or groundmass of rock is the fine-grained mass of material in which larger grains or crystals are embedded. ... This article is about a type of volcanic glass. ... Tachylyte is a vitreous form of basaltic obsidian (volcanic glass). ... This article is about the material. ...
Cryptocrystalline is a rock texture which is so finely crystalline, that is, made up of such minute crystals that its crystalline nature is only vaguely revealed even microscopically in thin section by transmitted polarized light.
Among the sedimentary rocks, chert and flint are cryptocrystalline.
Volcanic rocks, especially of the acidic type such as felsites and rhyolites, may have a cryptocrystalline groundmass as distinguished from pure obsidian (acidic) or tachylyte (basic), which are natural rock glasses.
Generally speaking, tools that require a sharp edge are made using cryptocrystalline materials that fracture in an easily-controlled conchoidal manner.
Cryptocrystallinetoolstones include flint and chert, which are fine-grained sedimentary materials; rhyolite and felsite[?], which are igneous flowstones[?]; and obsidian, a form of natural glass created by igneous processes.
Whereas cryptocrystalline materials are most useful for killing and processing animals, large-grained materials are usually used for processing plant matter.
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