Mozarkite is a 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 prec ...

(

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 start fir ...

). It is the

state rock Leaders of states in the U.S. which have significant mineral deposits often create a state mineral, rock, stone or gemstone to promote interest in their natural resources, history, tourism, etc. Not every state has an official state mineral, rock, ...

Missouri Missouri is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. Ranking List of U.S. states and territories by area, 21st in land area, it is bordered by eight states (tied for the most with Tennessee ...

. The name is a

portmanteau A portmanteau word, or portmanteau (, ) is a blend of wordsOzarks), and ''ite'' (meaning rock). Mozarkite consists essentially 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 one ...

(

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 form ...

- SiO₂) with varying amounts of chalcedony. It has won distinction as a particular form or variety of chert because of its unique variation of colors and its ability to take a high polish. It has the hardness of 7-7.5 on the

Mohs scale The Mohs scale of mineral hardness () is a qualitative ordinal scale, from 1 to 10, characterizing scratch resistance of various minerals through the ability of harder material to scratch softer material. The scale was introduced in 1812 by th ...

, which qualifies it as a suitable material for semi-precious gemstone, and has a density of about 2.65 g/cm³. Typically, the colors are different hues of red, pink, and purple with varying tints of green, gray and brown. It is collected and admired by lapidarists across the country. Interest in collecting mozarkite in Missouri started in the early 1950s, in Benton County, Missouri. It is found primarily in west-central Missouri, south of the Missouri River, and west of the Lake of the Ozarks. Mozarkite occurs in the

Cotter Dolomite Cotter may refer to: *Cotter pin (disambiguation), a pin or wedge used to fix parts rigidly together *Cotter (farmer), the Scots term for a peasant farmer formerly in the Scottish highlands *Cotter (surname), a surname (including a list of people w ...

of Ordovician age, which means it is some 450 million years old. It is found in residual boulders in the soil on hill slopes, along ditches, and in roadcuts where the boulders are exposed in the soil formed by weathering of the Cotter Dolomite.

State Rock

* Mozarkite was designated the official state rock of Missouri by the 74th Missouri General Assembly in 1967.

References

*Missouri Department of Natural Resources, Geological Survey and Resource Assessment Division fact sheet number 23; PUB 000653; 6/2002 {{Silica minerals Chert Lithics Symbols of Missouri Quartz gemstones