Mozarkite
Encyclopedia
Mozarkite is a form of chert
(flint
). It is the state rock of Missouri
. The name is a portmanteau, formed from Mo (Missouri), zark (Ozarks), and ite (meaning rock).
Mozarkite consists essentially of silica (quartz
- 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, 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 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.
.
Chert
Chert is a fine-grained silica-rich microcrystalline, cryptocrystalline or microfibrous sedimentary rock that may contain small fossils. It varies greatly in color , but most often manifests as gray, brown, grayish brown and light green to rusty red; its color is an expression of trace elements...
(flint
Flint
Flint is a hard, sedimentary cryptocrystalline form of the mineral quartz, categorized as a variety of chert. It occurs chiefly as nodules and masses in sedimentary rocks, such as chalks and limestones. Inside the nodule, flint is usually dark grey, black, green, white, or brown in colour, and...
). It is the state rock of Missouri
Missouri
Missouri is a US state located in the Midwestern United States, bordered by Iowa, Illinois, Kentucky, Tennessee, Arkansas, Oklahoma, Kansas and Nebraska. With a 2010 population of 5,988,927, Missouri is the 18th most populous state in the nation and the fifth most populous in the Midwest. It...
. The name is a portmanteau, formed from Mo (Missouri), zark (Ozarks), and ite (meaning rock).
Mozarkite consists essentially of silica (quartz
Quartz
Quartz is the second-most-abundant mineral in the Earth's continental crust, after feldspar. It is made up of a continuous framework of SiO4 silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall formula SiO2. There are many different varieties of quartz,...
- SiO2) with varying amounts of chalcedony
Chalcedony
Chalcedony is a cryptocrystalline form of silica, composed of very fine intergrowths of the minerals quartz and moganite. These are both silica minerals, but they differ in that quartz has a trigonal crystal structure, while moganite is monoclinic...
. 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, which qualifies it as a suitable material for semi-precious gemstone
Gemstone
A gemstone or gem is a piece of mineral, which, in cut and polished form, is used to make jewelry or other adornments...
, 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
Lapidary
A lapidary is an artist or artisan who forms stone, mineral, gemstones, and other suitably durable materials into decorative items such as engraved gems, including cameos, or cabochons, and faceted designs...
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
Missouri River
The Missouri River flows through the central United States, and is a tributary of the Mississippi River. It is the longest river in North America and drains the third largest area, though only the thirteenth largest by discharge. The Missouri's watershed encompasses most of the American Great...
, and west of the Lake of the Ozarks
Lake of the Ozarks
The Lake of the Ozarks is a large reservoir created by impounding the Osage River in the northern part of the Ozarks in central Missouri. Extents of three smaller tributaries to the Osage, the Niangua River, Grandglaize Creek, and Gravois Creek, are included in the impoundment...
. Mozarkite occurs in the Cotter Dolomite of Ordovician
Ordovician
The Ordovician is a geologic period and system, the second of six of the Paleozoic Era, and covers the time between 488.3±1.7 to 443.7±1.5 million years ago . It follows the Cambrian Period and is followed by the Silurian Period...
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 AssemblyMissouri General AssemblyThe Missouri General Assembly is the state legislature of the U.S. state of Missouri. The bicameral General Assembly is composed of a 34-member Senate, and a 163-member House of Representatives. Members of both houses of the General Assembly are subject to term limits...
in 1967
.