Texas Rocks and Minerals

Texas produces a large variety of gemstones, rocks, minerals and fossils.

Sandy sediments typical of the coastal plain make up southeastern Texas. Behind this lies the Llano uplift of central Texas and in far western Texas, this is a region of crystalline rocks. The Grand Prairie and Edwards Plateau, primarily sedimentary rocks, link the Llano uplift, to the north central plains and, toward the Panhandle, the High Plains themselves. In far western Texas is the Trans Pecos, formed of rugged mountains, both igneous and sedimentary in their structure.

Texas has been the leading state in petroleum production since discovery of the Spindletop oil field in 1901. Texas also produces coal, gypsum, ball clay, bentonite, construction and industrial sand and gravel, uranium, and zeolites. In the past, the state mined mercury, silver, and copper. Gold is also found in the state, but is limited. Most of the gold produced has come as the byproduct of silver and copper ores, but traces of it occur in the Shafter, Van Horn, Allamoore, and Quitman mountains, and in Howard, Taylor, Irion, Uvalde, and Williamson counties.

Native silver was officially declared the state mineral in 2007. The discovery of silver in Texas is credited to the Franciscan friars who discovered and operated mines near El Paso around 1680. The famous Presidio Mine operated from 1884 to 1947 and produced more than 90 percent of the silver that came from Texas. Silver was primarily found in western Texas, but there are no active silver mines any more. The mountainous areas of western Texas also produce uniquely banded agates, petrified wood, fossilized coral, dinosaur bones, and amethyst.

The Llano Uplift, a geologic dome of Precambrian gneiss, schist, and granite, is where you find the official state gemstone of Texas, blue topaz, declared in 1969. Topaz is most common in the central areas of Texas, such as Mason County and Llano County. Ranchers use to let rockhounds collect topaz on their property, but now the area is mostly closed off. The Lindsay Ranch, Seaquist Ranch and Bar M Ranch were among the most famous Pay for Dig locations, but it is my understanding that they are all closed now.

The Panhandle region produces a few agates and some petrified wood, but is best known for a unique variety of flint called Alibates, which can be pink or blue and was used by Native Americans to make tools. Petrified palm wood formed in the warm, wet regions of east Texas on the Texas/Louisiana border. Petrified palm wood was named the Texas state rock in 1969.

Beryl crystals have been found in pegmatite dikes in Llano, Blanco, and Gillespie counties. Fine crystals of both colorless and blue gem quality celestite have been found at Mount Bonnell and other localities west of Austin, Travis County. Fluorite occurs in several localities in Texas, notably in Hudspeth, Brewster, Presidio, Llano, Mason and Burnet counties, but not commonly in gem quality, size or colors that would make it valuable.

Good crystals of gem-quality almandite garnet have been found in southeast Llano, northwest Blanco, Burnet, and northeast Gillespie counties. The garnet mostly occurs in stream gravels where they can be collected after being weathered out. Garnets have been found in other locations, including Mason, El Paso, Hudspeth, and Culberson counties, but no stones of facet quality have ever been recorded from these areas.

Agates and jaspers are found in many areas of Texas, especially in the western and southern regions. Big Bend, Lobo Valley, and Bishop Ranch are known for high-quality agates. Jaspers are found in the Glass Mountains, Chinati Mountains, Eagle Pass, the Rio Grande and around Falcon Lake.

Even though northern Texas doesn’t have a lot of gem grade rocks and minerals, it does have fossils. Megalodon shark teeth, trilobites, corals, leaf print fossils, crinoids, and even dinosaur bones have been found in north Texas. Minerals Wells Fossil Park is one of the best places to search for fossils, but you can also find interesting fossils near Lake Bridgeport, the Pecos River, and Lake Whitney.

Turquoise is found in west Texas, including Culberson County, Van Horn, and the Carrizo Mountains, but it generally isn't as nice or valuable as the Turquoise found in Arizona or Nevada.

Before venturing out-do some research on where and what you can collect. Remember you must have permission to collect on private property.

See my page on Rockhounding Rules for general information on the rules of collecting rocks on various lands.