Cryptocrystallineis arock texturemade up of such minutecrystalsthat its crystalline nature is only vaguely revealed even microscopically[1]inthin sectionby transmittedpolarized light.Among thesedimentary rocks,chertandflintare cryptocrystalline.Carbonado,a form of diamond, is also cryptocrystalline.Volcanic rocks,especially of the felsic type such asfelsitesandrhyolites,may have a cryptocrystallinegroundmassas distinguished from pureobsidian(felsic) ortachylyte(mafic), which are natural rockglasses.Agateandonyxare examples of cryptocrystallinesilica(chalcedony). Thequartzcrystals in chalcedony are so tiny that they cannot be distinguished with the naked eye.[2]
See also
editReferences
edit- ^American Geological Institute(1984). Bates, Robert Latimer; Jackson, Julia A. (eds.).Dictionary of geological terms(3rd ed.). Garden City, New York:Anchor Press/Doubleday.p. 120.ISBN0385181000.OCLC9412868.
- ^Jesse, Dorothea."How Hard is Agate on the Mohs Scale".RetrievedJuly 5,2024.
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