Despite preconception of a dry, deserty Texas, the Lone Star State contains a wide variety of geographical features, less than 10% of which is desert. This is, in part, due to the state being the 2nd largest in the country by land.
This diversified landscape gives rise to rocks of all type and makes the state a treasure trove of some of rarest gemstones and minerals.
Minerals and Gemstones Found In Texas
Taking on a range of stunning colors and names, beryl is a gemstone of remarkable beauty. Two of its notable forms are emeralds and aquamarines. It’s the aquamarine type of beryl that can be found in Texas.
Fine blue gemstone-quality beryls are formed in the Franklin Mountains. This blue pigment comes from an impurity of reduced iron. Other beryl varieties may be found in the pegmatite dikes in Llano and Gillespie Counties.
Beryl more fully is beryllium aluminum cyclosilicate, though this is not where its name originates. Actually, the fourth element, beryllium, was named after the gemstone, which was discovered centuries prior. Beryl comes from the Greek meaning precious blue stone.
One of the first known uses of beryl is as eyeglasses in the 13th century, though some reports date this back further. Owing to its 7.5 Mohs hardness, beryl is used in several types of jewelry and aesthetic pieces.
The 30th element can be found in many ores within Texas. Zinc is found in high quantities both naturally and as its chief mineral, sphalerite, in the Apache and Quitman Mountains of the Lone Star State.
As a hot liquid, zinc rises from the mantle and cools into igneous rock hollows. Over time these can collect in larger quantites and be mined.
Zinc has several uses, including medicinal ones. It is an essential mineral and required for human growth. Many medications use it as a co-factor, as well.
One of its earliest known uses is in metallurgy. There, it was combined with copper to make the alloy known as brass.
This dark green mineral can be hard to describe due to its widespread nature. Augite is a rock-forming mineral, meaning that it composes more than 90% of the rocks in the Earth’s crust. Notably, this includes basalts and gabbros.
Augite itself is part of a group of minerals known as pyroxenes. These are named after the Greek words for fire stranger, as they were considered impurities following a volcanic eruption. These minerals form in weathered hollows of igneous rocks.
This is true for those found in Eagle Flat, Texas. There, shinier versions of augite may be found. Though its name comes from the Greek word for brightness, most samples of it appear dull.
Augite’s uses are predominantly academic and collectible. Most use samples to learn about the geological history of an area. They have also been found on the moon and meteorites.
Chalcedony is a catch-all that refers to several semi-precious gemstones with a microcrystalline silica structure. This means that its crystals are so small to only be seen with a microscope. Depending on what impurities are present during its formation, chalcedony can refer to agate, jasper, carnelian, and more.
In Texas, it is mostly moss agates that are found. Sometimes dubbed blue cheese, these stones are not true agates, as they lack concentric bands. They are found in Brewster County.
Chalcedony is another mineral type present amount many civilizations, and is even mentioned in the Bible’s Book of Revelations. In prehistory, it was used in conjunction with stone to fashion knives. During the Bronze Age, they were used to make cameos.
Today, these waxy minerals are used for jewelry and crafting small figurines. They are mainly ornamental and can be found in many local rock shops.
This burnt orange gemstone is actually fossilized tree resin, rather than carefully crafted silica and minerals. Millions of years after an injured tree secretes resin to protect itself, this gemstone solidifies into what is seen today. Its formation gives rise to one of its most prolific uses: science.
Oftentimes, fossils or insects will be preserved within the amber. This allows scientists to study prehistoric ecosystems. Perhaps, this is why some refer to amber as nature’s time capsule.
Amber, too, is praised for its beauty. However, due to its soft nature (2.0 on the Mohs scale), it cannot be used in all types of jewelry. Today, it is mainly used in broaches and necklaces.
Texas has many caches of amber. The best places for amber prospectors in Texas are the Gulf Coastal Plain and along the Terlingua Creek. There small, but high-quality amber can be found.
Known for being radioactive, uranium is an interesting find in the Lone Star State. It was first discovered there in Karnes County in the 1950’s. Now, it can be found in the Trans-Peco area and the High Plains.
The 92nd element is part of the actinide series, and though it does have a radioactive isotope, it has many less deadly uses. It was first used, as many early minerals, to dye glazes. Several centuries-old ceramics have been found to have a yellow sheen due to a 1% trace of uranium.
Interestingly enough, uranium is relatively common within the Earth’s crust, where it is 40 times more concentrated that silver. It is the 51st most abundant element within the Earth and is found in significant quantities in many other minerals, including lignite.
Garnets are silicate minerals, having a range of colors due to impurities. That being said, they typically are dark red in appearance.
Though debated, their name comes from the Middle English word for dark-red. Another report attributes the name to an Old French word for seed. In either case, older cultures clearly valued the gemstone.
Throughout history, garnets have been prized for their uses in jewelry. Garnets are also used industrially as an abrasive, due to their relative hardness.
Lignite is a moist brown coal. It contains 20-35% carbon by mass. This makes lignite the ideal coal for use at a steam-electric power station.
There, lignite is used to generate electricity with a steam engine. Typically, these power stations provide electricity for the surrounding towns and are located near the coal mine. The Monticello steam-electric station in Mount Pleasant produced 1.8 Gigawatts of power, before being shut down in 2018.
Lignite is still mined and used for energy in Texas today. It can be found along the Colorado river and in the Texas coastal plain. This is due to its formation as peat sediments over time.
Depending on the year, Texas is and has been the fourth biggest producer of lignite in the United States. In an insightful 2015 report, the state details lignite’s economic impact, providing over 24,000 jobs and more than 7 billion dollars.
A mystical, purple quartz, amethyst has been used across cultures for its beauty and metaphysical attributions. The Greeks thought it prevented one from becoming intoxicated, as its literal translation means not drunken. Nearly every major civilization since then has given the stone some ulterior use.
Buddha considered it a sacred stone, and so Tibetan prayer beads are made of it. As a nod to the Greeks, Catholic bishops set their rings in amethyst. Today, it has become the Western birthstone of February.
Perhaps, one of the reasons for this cross-cultural relevance is its uniform purple color, which is rare in nature. The color arises from transition metal impurities and in some cases irradiation.
In Texas, a group of geologists named the Amethyst Mountains, thinking it contained a wealth of the purple gemstones. Later, it was discovered to be a bit misguided. Now, amethyst prospectors can look to West Texas and Lampass.
The 79th element and historically hunted mineral, gold has helped define local economies and townships. Civilizations across time and space have cherished the reddish-yellow mineral, and in some cases waged war over it. Like many others, the Aztecs believed gold came from the gods themselves.
With a Mohs hardness of just 2.5, gold tends to be used sparingly in figurines and usually to add ornamentation. It is, of course, widely used in jewelry and other aesthetic pieces. Gold, however, can also be found in food and certain medications.
Despite its ubiquitous nature, gold’s formation is largely unknown. Some theories claim it to be from supernovas, while other claim it has always originated in the Earth’s mantle. Either way, gold ores are found in rocks dating as far back as Precambrian times.
In Texas, gold was first found in 1942. Most of the remaining gold in the state can be found in the West. The Presido and Hazel Mountain ranges contain large gold ores.