During World War II, Morefield Mine , located just outside of Richmond, Virginia, was used by military suppliers in search of strategic minerals like mica, beryl and tantalum for use in tanks and artillery. Located feet under ground and stretching 2, feet in length, the mine is always growing and changing. The area formed more than million years ago when magma pushed from the center of the earth to the surface and cooled, leaving behind massive deposits of minerals.
The mine owners periodically use explosives to blast the cave and open up new areas for visitors to explore. Several times each year, the caretakers of Graves Mountain , located about miles east of Atlanta, invite visitors to dig for buried treasure at this site, which formed millions of years ago when sedimentary rocks metamorphosed.
Large traces of the mineral can still be found there today. Jennifer Nalewicki is a Brooklyn-based journalist. You can find more of her work at her website. American South A Smithsonian magazine special report. Here are five public dig sites worth rolling up your sleeves for: Emerald Hollow Mine Hiddenite, North Carolina Emerald Hollow Mine in Hiddenite, North Carolina, offers multiple gem hunting opportunities for visitors: digging, creeking and sluicing.
Graves Mountain Lincolnton, Georgia Graves Mountain in Lincolnton, Georgia, is a hotbed for numerous gems and minerals, including turgite, which is known for its iridescent coloration. James St. Post a Comment. The first is to look for any flaws. While this may seem counterintuitive, flaws in the colour or texture, especially vein-like impurities when looked at under the microscope, could indicate a natural stone. Jade is a stone that is most commonly green, although it can come in other colours like purple and white.
Jade is two different minerals: nephrite and jadeite. Since ancient times, Jade has been used in jewellery and sculptures and is often used to make jewellery beads. It was also used as a tool in ancient times. In its rough form, it has a dull, greenish colour. This is a dark green gemstone with rings, giving it a distinctive appearance. It usually forms within the limestone. It is often used to make beads and is used to make ornate carvings and, until the 16th century, it was often used as a pigment for painting.
In the United States, it is most commonly found in Arizona. Obsidian is an igneous rock. It forms when molten rock cools and is technically a mineraloid.
Obsidian is usually associated with the colour black, but it can come in other colours as well, including green and brown. Stone Age cultures used it as a cutting tool. Today, obsidian is sometimes used as a surgical cutting tool. It is also popular in jewellery and can be shaped into gemstone beads. Opal is a form of silica, and precious opal has an iridescent quality that makes it appealing. Some rare opals can be more valuable than diamonds.
It comes in a variety of colours, including white, black, purple, pink, brown, and green. Black opals are the most desired form of opal. White opals and fire opals are also popular. They are often used in jewellery, and common opals can also be used to carve figures.
Opals in the rough have an iridescent quality, making them relatively easy to find. It can be found in Idaho, California, Oregon, and Nevada, and it is the birthstone for those born in October. Peridot is the gemstone version of the mineral olivine. It is usually found in green colour variations due to the amount of iron in the olivine. Olivine is usually found in igneous rocks. As a gemstone, the peridot is relatively soft.
It is easy to scratch and can burst under pressure. Peridot can be found in Arizona, Hawaii, and Colorado, and olivine in the rough has a distinctive green colour. Quartz is one of the easiest materials to find. Amethyst, agate, carnelian, and citrine are some gemstone varieties of quartz. Examples include: zircon , topaz , ruby , etc. This movie shows formation of crystals such as ruby or zircon pink crystals and topaz in open cavities e. Metamorphic gems Metamorphic rocks are rocks changed by heat, pressure, and interaction with solutions.
There are a number of types of metamorphic environments: Plate tectonics creates metamorphic environments characterized by high temperature and high pressure - produce jadeite jade. In extremely rare cases, pressures in metamorphic rocks may be high enough that diamonds form. Regionally metamorphosed rocks: large volumes of rock that are buried and changed in response to increases in pressure and temperature. Minerals found in these rocks might include gems such as garnet and cordierite.
This movie shows metamorphism of rocks resulting from continent-continent collision associated with a subduction zone. Note the formation of large crustals such as garnet in the deformed, heated zone. This movies illustrates the process of contact metamorphism. This is the process by which the minerals in rocks change in response to proximity to a hot intrusive body. For example, a limestone intruded by a magma undergoes significant change in crystal size, mineral content, and chemistry due to addition of solutions released from the cooling magma.
These rocks contain gems such as garnet. Gems formed in the mantle The most abundant upper mantle mineral is olivine peridot. Slabs of mantle material are brought to the surface through tectonic activity and volcanism. Deep mantle gems. Rocks such as kimberlites are erruptive volcanics that come from quite deep in the mantle and carry with them diamonds. Diamonds are made from carbon. 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 also include many varieties of agate, jasper, jade , garnet , and quartz. The state is one of the only sources of benitoite , a blue barium titanium silicate, and it has been named the state gemstone. The image at right is a Vesuvianite cabochon cut from material produced at the Happy Camp mine in Siskiyou County. Learn more about California Gemstones. 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.
Amethyst , garnet , jasper, agate, and opals are also found at numerous locations in the state. Utah also has the world's only locality where beautiful purple Tiffany Stone can be found. Tennessee is well-known for a single gem material - pearls. 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.
Learn more about Tennessee gemstones. Montana's most popular gemstone product is sapphire. Yogo Gulch sapphires have been famous for over 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 often produced by heat treatment. Some gem-grade garnets are also produced from the alluvial deposits.
Rockhounds in many parts of Montana enjoy looking for agate and jasper. One of the most popular is "Montana Moss Agate," a transparent to translucent material that usually has brown to black bands or "moss" in a wide variety of patterns. Learn more about Montana gemstones. 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 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 Mountain. Rhodochrosite is the state mineral, and many specimens are cut into gemstones such as the stone shown here from the Sweet Home Mine.
Learn more about Colorado Gemstones. 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 can pay a fee, look for minerals and keep what you find.
Arkansas's most important gem material is quartz. In Arkansas, clear quartz is often called "rock crystal. Exceptional specimens of rock crystal can sell for thousands of dollars. Clear, undamaged single crystals are made into pendants, earrings and other types of jewelry.
In addition to rock crystal, Arkansas produces other quartz gems including agate, chert , jasper, opal , petrified wood , and smoky quartz frequently heat-treated rock crystal.
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