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Flint, occasionally flintstone, is a sedimentary cryptocrystalline form of the mineral quartz, [1] [2] categorized as the variety of chert that occurs in chalk or marly limestone. Historically, flint was widely used to make stone tools and start fires. Flint occurs chiefly as nodules and masses in sedimentary rocks, such as chalks and limestones.
Hertfordshire puddingstone is a silica-cemented conglomerate composed of rounded flint pebbles and cobbles with matrix of fine sand and silica cement. The Hertfordshire Puddingstone is characterized by silica-cemented flint gravel that is brown to deep red in colour and often exhibits black exteriors and thin rinds on cut or polished surfaces.
Flint – Cryptocrystalline form of the mineral quartz; Geyserite – Form of opaline silica often found around hot springs and geysers; Greywacke – Sandstone with angular grains in a clay-fine matrix; Gritstone – Hard, coarse-grained, siliceous sandstone; Ironstone – Sedimentary rock that contains a substantial proportion of iron ore
Natural stone is used as architectural stone (construction, flooring, cladding, counter tops, curbing, etc.) and as raw block and monument stone for the funerary trade. Natural stone is also used in custom stone engraving. The engraved stone can be either decorative or functional. Natural memorial stones are used as natural burial markers.
According to Marble.com, in 2016 there were 276 quarries producing natural stone in 34 states, and states producing the most granite were Texas, Massachusetts, Indiana, Wisconsin, and Georgia. [1] The term "quarry" refers also to sites producing aggregate, molding sand, or other resources besides cut stone.
Two distinct styles exist; the first is a style of carved flint clay found over a wide geographical area but believed to be from the American Bottom area and manufactured at the Cahokia site specifically; the second is a variety of carved and polished locally available stone primarily found in the Tennessee-Cumberland region and northern ...
Upper Jurassic striped flint from Lesser Poland consists mainly of α-quartz. Morphology of grains indicates that the quartz is not a product of opal and chalcedony conversion, but it precipitated directly from the seawater. The crystallinity is higher in the centre of a concretion. Sometimes chalcedony is present, being a product of ...
In geology, clay-with-flints is the name given by William Whitaker in 1861 to a peculiar deposit of stiff red, brown, or yellow clay containing unworn whole flints as well as angular shattered fragments, also with a variable admixture of rounded flint, quartz, quartzite, and other pebbles.