Novaculite, also called Arkansas Stone, is a

microcrystalline A microcrystalline material is a crystallized substance or rock that contains small crystals visible only through microscopic examination. There is little agreement on the range of crystal sizes that should be regarded as microcrystalline, but th ...

cryptocrystalline Cryptocrystalline is a rock texture 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 crypt ...

rock type that consists of

silica Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , most commonly found in nature as quartz and in various living organisms. In many parts of the world, silica is the major constituent of sand. Silica is ...

in the form of

chert Chert () is a hard, fine-grained sedimentary rock composed of microcrystalline or cryptocrystalline quartz, the mineral form of silicon dioxide (SiO2). Chert is characteristically of biological origin, but may also occur inorganically as a ...

flint Flint, occasionally flintstone, is a sedimentary cryptocrystalline form of the mineral quartz, categorized as the variety of chert that occurs in chalk or marly limestone. Flint was widely used historically to make stone tools and sta ...

. It is commonly white to grey or black in color, with a

specific gravity Relative density, or specific gravity, is the ratio of the density (mass of a unit volume) of a substance to the density of a given reference material. Specific gravity for liquids is nearly always measured with respect to water at its densest ...

that ranges from 2.2 to 2.5. It is used in the production of

sharpening stone Sharpening stones, or whetstones, are used to sharpen the edges of steel tools such as knives through grinding and honing. Such stones come in a wide range of shapes, sizes, and material compositions. They may be flat, for working flat edg ...

s. It occurs in parts of

Arkansas Arkansas ( ) is a landlocked state in the South Central United States. It is bordered by Missouri to the north, Tennessee and Mississippi to the east, Louisiana to the south, and Texas and Oklahoma to the west. Its name is from the O ...

, Oklahoma, and

Texas Texas (, ; Spanish: ''Texas'', ''Tejas'') is a state in the South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2020, it is the second-largest U.S. state by ...

, as well as in Japan and parts of the

Middle East The Middle East ( ar, الشرق الأوسط, ISO 233: ) is a geopolitical region commonly encompassing Arabia (including the Arabian Peninsula and Bahrain), Asia Minor (Asian part of Turkey except Hatay Province), East Thrace (Europ ...

. The name ''novaculite'' is derived from the

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

word ''novacula'', meaning a sharp knife, dagger, or razor, in reference to its use in sharpening. The first recorded use of the term '' whetstone'' was in reference to a honing stone from Arkansas.

Occurrence

Novaculite beds are present in the

Ouachita Mountains The Ouachita Mountains (), simply referred to as the Ouachitas, are a mountain range in western Arkansas and southeastern Oklahoma. They are formed by a thick succession of highly deformed Paleozoic strata constituting the Ouachita Fold and Thru ...

and Oklahoma, and in the Marathon Uplift and

Solitario The Solitario (''El Solitario'') is a large geologic formation in Big Bend Ranch State Park (Texas), Big Bend Ranch State Park in West Texas. When viewed from above, it suggests an impact crater; though it is actually the eroded remains of a lacco ...

regions of

. Novaculite is very resistant to

erosion Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is dis ...

and the beds stand out as ridges in the Ouachita Mountains. There are also occurrences in Japan, Syria,

Lebanon Lebanon ( , ar, لُبْنَان, translit=lubnān, ), officially the Republic of Lebanon () or the Lebanese Republic, is a country in Western Asia. It is located between Syria to Lebanon–Syria border, the north and east and Israel to Blue ...

, and

Israel Israel (; he, יִשְׂרָאֵל, ; ar, إِسْرَائِيل, ), officially the State of Israel ( he, מְדִינַת יִשְׂרָאֵל, label=none, translit=Medīnat Yīsrāʾēl; ), is a country in Western Asia. It is situated ...

Origin

The novaculite beds of the south-central United States were deposited in the Ouachita Geosyncline, a deep-water marine trough, during Silurian to early Mississippian time. Sedimentation consisted primarily of

siliceous Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , most commonly found in nature as quartz and in various living organisms. In many parts of the world, silica is the major constituent of sand. Silica is one ...

skeletal particles of marine organisms such as

sponge spicule Spicules are structural elements found in most sponges. The meshing of many spicules serves as the sponge's skeleton and thus it provides structural support and potentially defense against predators. Sponge spicules are made of calcium carbon ...

s and

radiolaria The Radiolaria, also called Radiozoa, are protozoa of diameter 0.1–0.2 mm that produce intricate mineral skeletons, typically with a central capsule dividing the cell into the inner and outer portions of endoplasm and ectoplasm. The el ...

, and very fine-grained, wind-blown

quartz Quartz is a hard, crystalline mineral composed of silica ( silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical ...

particles; there was very little

argillaceous Clay minerals are hydrous aluminium phyllosilicates (e.g. kaolin, Al2 Si2 O5( OH)4), sometimes with variable amounts of iron, magnesium, alkali metals, alkaline earths, and other cations found on or near some planetary surfaces. Clay minerals ...

sedimentation during novaculite deposition.McBride, E.F. and Thomson, A. 1970. The Caballos novaculite, Marathon region, Texas. Geological Society of America, Special Paper 122, 129. p. The novaculite beds were later subjected to folding and uplift, and probably low-grade

metamorphism Metamorphism is the transformation of existing rock (the protolith) to rock with a different mineral composition or texture. Metamorphism takes place at temperatures in excess of , and often also at elevated pressure or in the presence of ch ...

, during the Ouachita orogeny in early Pennsylvanian time.

Use

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Because novaculite is very hard and dense, it has been mined since prehistoric times, first for use as arrow and spear points, and later to make sharpening stones. Novaculite-rich sharpening stones from Arkansas are called ''Arkansas stones''; stones produced in the

Ottoman empire The Ottoman Empire, * ; is an archaic version. The definite article forms and were synonymous * and el, Оθωμανική Αυτοκρατορία, Othōmanikē Avtokratoria, label=none * info page on book at Martin Luther University) ...

(Syria, Lebanon, and Israel) were called ''Turkey stones''; and novaculite stones were also produced in Japan. The weathered upper strata of Arkansas novaculite, known as tripoli or "rotten stone", are rich in silica and have found a niche market as a performance additive or filler in the coatings, adhesives, sealants, and elastomer industries. Tripoli is mined just east of

Hot Springs, Arkansas Hot Springs is a resort city in the state of Arkansas and the county seat of Garland County. The city is located in the Ouachita Mountains among the U.S. Interior Highlands, and is set among several natural hot springs for which the city is n ...

by the Malvern Minerals Company.Nichols, John C., ''Minerals on the Ouachita National Forest,'' USDA Forest Service 12 May 2008
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References

{{Reflist * Folk, R.L., and E.F. McBride, 1976, ''The Caballos Novaculite revisited Part I: "origin of novaculite members ''. Journal of Sedimentary Petrology. 46659-669 * Folk, R.L., and E.F. McBride, 1978, ''Origin of the Caballos Novaculite''. in S.J. Mazzullo, ed., Tectonics and Paleozoic facies of the Marathon Geosyncline, West Texas: Permian Basin Section, Society for Sedimentary Geology, SEPM, Publication no. 78-17:101-130. * Frondel, C., 1962, ''The System of Mineralogy of J. D. and E. S. Dana, v. 3, Silica Minerals'': 7th ed., John Wiley and Sons, New York, 334p. * King, P.B., 1937

United States Geological Survey The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, ...

Professional Paper 187 * Krumbein, W.C. and Sloss, L.L., 1963, ''Stratigraphy and Sedimentation'': 2nd ed., W. H. Freeman and Company, San Francisco, 660p. * Lowe, D.R., 1975, ''Regional Controls on Silica Sedimentation in the Ouachita System''.

Geological Society of America The Geological Society of America (GSA) is a nonprofit organization dedicated to the advancement of the geosciences. History The society was founded in Ithaca, New York, in 1888 by Alexander Winchell, John J. Stevenson, Charles H. Hitch ...

Bulletin. 86:1123-1127 * Lowe, D.R., 1976, ''Nonglacial varves in lower member of Arkansas Novaculite (Devonian), Arkansas and Oklahoma''.

American Association of Petroleum Geologists The American Association of Petroleum Geologists (AAPG) is one of the world's largest professional geological societies with more than 40,000 members across 129 countries as of 2021. The AAPG works to "advance the science of geology, especially as ...

Bulletin. 60:2103-2116. * Lowe, D.R., 1977, ''The Arkansas novaculite: some aspects of its physical sedimentation''. in C.G. Stone, and others, eds., Symposium on the geology of the Ouachita Mountains. Arkansas Geological Commission Miscellaneous Publication 13:132-138. * Lowe, D.R., 1989, ''Stratigraphy, sedimentology, and depositional setting of pre-orogenic rocks of the Ouachita Mountains, Arkansas and Oklahoma'', in R.D. Hatcher, Jr., W.A. Thomas, and G.W. Viele, eds., The Appalachian-Ouachita orogen in the United States. The Geology of North America. F-2:575-590, Geological Society of America, Boulder. * McBride, E.F., 1989, ''Stratigraphy and sedimentary history of Pre-Permian Paleozoic rocks of the Marathon uplift'', in R.D. Hatcher, Jr., W.A. Thomas, and G.W. Viele, eds., The Appalachian-Ouachita orogen in the United States. The Geology of North America. F-2:603-620, Geological Society of America, Boulder.

External links

Arkansas Geological Commission: ''Novaculite''

* ttps://web.archive.org/web/20201110020239/http://archeology.uark.edu/novaculite/index.html Arkansas Archeological Survey: ''Arkansas Novaculite: A Virtual Comparative Collection'' Minerals Economic geology Industrial minerals Ouachita Mountains Sedimentary rocks Chert