State Rocks, Minerals, & Gems


State mineral: quartz

Arkansas produces some of the highest quality quartz crystals in the world. Most of the state’s quartz deposits are found in the Ouachita Mountains, where they crystallized into veins from hydrothermal solutions during the last phases of mountain building.

State rock: bauxite

This reddish brown rock is made up of chemically weathered Paleocene soils that were consolidated through weathering processes. Bauxite is a principle ore of aluminum and is economically important in Arkansas.

State gem: diamond

The diamonds of Arkansas originated in the mantle, where they crystallized approximately three billion years ago. Today, they are found in the remains of a 95-million-year-old eroded volcano whose exposed lava pipes were channels for magma that brought these diamonds from the mantle to the surface.


Kansas has no state rocks or minerals.


State mineral: agate

Agate found in Louisiana today was originally formed in the limestones of the central US, where it precipitated from silica-rich liquids. After erosion released it from its original bedrock, the banded stone was carried into the state by ancient rivers.

The designated state “gem” is eastern oyster shell.


State mineral: galena

Missouri is nicknamed “the Lead State” due to the prevalence of this shiny cubic mineral, the natural form of lead. Thanks to rich deposits of galena, Missouri is the largest producer of lead in the United States.

State rock: mozarkite

This colorful form of chert consists of silica and chalcedony, and is found in the Ordovician deposits of west-central Missouri. Its name is a portmanteau of Missouri (mo), Ozarks (zark), and the suffix -ite, meaning “rock.”


State rock: barite

Also known as “desert rose,” these flower-like rock formations may be composed of large crystals of gypsum, selenite, or other evaporite minerals. Oklahoma’s barite crystallized 250 million years ago during the Permian.


State mineral: silver

Silver was first discovered in Texas in 1880, and has been mined intermittently since then.

State rock: petrified palmwood

Although technically a fossil, petrified palmwood became Texas’ state “rock” in 1969. Dying trees from the lush Cretaceous forests were occasionally covered by mud before decaying; their cellular structures were replaced by silicate minerals to form petrified wood.

State gem: Texas blue topaz

This silicate gemstone is only found in Mason County, near the Llano Uplift, where it occurs in Precambrian granite outcroppings. The largest gem-quality topaz ever found in Texas (and all of North America) weighs in at a whopping 1296 grams (2.8 pounds)!