A variety of gemstones have been found in Nevada, and the state is well-known for its opal. After Australia, some of the finest black opals in the world come from Virgin Valley, Nevada. The specimen shown here is a 9-millimeter faceted yellow fire opal of about 1.79 carats, cut from rough produced in Nevada. The state is also well-known…

Most people would not think of Louisiana as a “gemstone state.” However, it is the source of a unique variety of precious opal and a source for abundant amounts of “petrified palm wood.” The palm material found in the Catahoula Formation, a sedimentary rock unit deposited during Oligocene time, is so popular and well-known that the state…

The first commercial gemstone mine in the United States that was operated by miners who were not Native Americans was at Mount Mica, Maine. There a large deposit of tourmaline was discovered by children in 1820. Two years later a mine was opened and it yielded thousands of carats of gem-quality tourmaline crystals. Since then the pegmatite deposits of…

Idaho’s nickname is “The Gem State.” It has a long history of producing a variety of gem materials. The most important gems produced to date have been star garnet and opal. Notable amounts of jade, topaz, zircon, and tourmaline have also been found in Idaho. Agate, jasper, and petrified wood in many colors and patterns have been found and produced from small deposits throughout the state.

The most popular gemstone locality in Arkansas is Crater of Diamonds State Park, where anyone can pay a fee, look for diamonds, and keep any that are found. The site is an operating state park, and visitors usually find hundreds of small diamonds every year. There are several other fee mining areas in the state where you…

Many different gemstones are produced in Colorado. These include aquamarine, amazonite, garnet, topaz, tourmaline, lapis lazuli, quartz, smoky quartz, rhodochrosite, rose quartz, amethyst, turquoise, peridot, sapphire, zircon, agate, and jasper. A rough diamond from Colorado was cut into a 16.87-carat stone. It is the largest cut diamond ever produced from United States rough. Aquamarine is the state gemstone of Colorado, and it is mostly found at high elevations on Antero…

Montana’s most popular gemstone product is sapphire. Yogo Gulch sapphires have been famous for over 100 years, and the production of sapphires in Montana continues today. Sapphires are produced from both rock and alluvial deposits. They occur in a wide range of colors which include blue, blue-green, green, pink, pale red, purple, yellow, and orange (colors…

Tennessee is well-known for a single gem material – pearls. The American Pearl Company operates the only freshwater pearl farm in the United States. They produce cultured freshwater pearls from native river mussels. The coin-shaped pearls in the photo are from the American Pearl Company and display iridescent shades of golden, pink, and blue.

Utah produces a wide variety of gemstones. Although topaz is Utah’s state gemstone, the gemstone that is getting a lot of recent attention is red beryl, also known as bixbite. The faceted red beryl shown here from the Wah Wah Mountains is a beautiful example. Amethyst, garnet, jasper, agate, and opals are also found at numerous locations in the state. Utah…

California is widely known for its tourmaline and turquoise production. Native Americans were the first to treasure these minerals, and a commercial gemstone industry was active by the late 1800s. The tourmaline deposits of Riverside and San Diego Counties have supplied more tourmaline for cutting and mineral specimens than any other tourmaline deposits in the northern hemisphere. California gemstones…