Mozarkite
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/cm. 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.