Although Australia is the world's largest supplier of this mesmerising gemstone, opal aficionados will be pleasantly surprised by the variety of locales in the United States that provide this precious gem. The US has a long history of opal discovery and a thriving gem-hunting society, even though Australia supplies a significant portion of the world's opal supply. The main areas of the United States that are rich in opals are located in areas with geothermal activity, in distant highlands, and in volcanic rock formations. For style inspiration after a successful dig, explore handcrafted opal engagement rings that showcase natural play-of-colour.
Understanding Opal and Its Formation
Opal, in contrast to other minerals, does not possess a crystalline structure since it is a hydrated amorphous form of silica (SiO₂·nH₂O). Light is reflected off of the tiny silica spheres that are structured in a regular pattern inside the stone, giving it its distinctive "play-of-colour" quality. The inside structure of this object scatters light, resulting in a mesmerising display of shifting hues. In sedimentary rocks, ash beds from volcanic eruptions, or fissures and crevices in other kinds of rocks, opals usually develop when silica-rich solutions seep through and crystallise over millions of years. Opals may contain anything from three percent to twenty-one percent water by weight.
Opals may be classified into two basic types: common opals, which do not display play-of-colour, and valuable opals, which do. Black opal, the rarest and most valuable of precious opals, is greatly sought after due to its intense black colour. For a deeper dive into what makes black opal special, see our guide to black opal brilliance. More common and often showing a milky or hazy sheen are common opals, which include milk opals, resin opals, wood opals, and hyalite.
The Best U.S. Sites to Find Opals
Opportunities abound for both experienced prospectors and beginner gem seekers in a number of US states famous for their opal deposits. For background on U.S. gemstone resources, see the USGS opal overview.
State of Nevada
In particular, the Virgin Valley area of Humboldt County in Nevada is well-known as one of the best places in the United States to go opal searching. Numerous valuable opal varieties, such as black, crystal, white, fire, and lemon opals, are famously mined in this region. Even Nevada's official gemstone is the black fire opal. Specimens of Virgin Valley opals, some of which are enormous and highly prized, are often discovered in lieu of wood or other plant materials. Popular Virgin Valley mines that are available to the general public include:
Rainbow Ridge Opal Mine
This mine, which the Hodson family has owned and run since 1949, is open for fee mining from May to September. Guests have the option to choose between loading on virgin ground or tailings. Over $50,000 has been put on some of the opals found here. Learn more at the Rainbow Ridge Opal Mine official site. If the rich body tones of Virgin Valley inspire a jewellery idea, consider a refined platinum black opal ring with deep blue-green flashes.
Royal Peacock Opal Mine
The Royal Peacock has been welcoming visitors since 1981 and is known to have produced some exceptional precious opal specimens. In addition to features like a souvenir store and RV campground, it provides services like bank excavating and tailings sorting. Only one mine has ever been found to contain luminous opal. Details available at the Royal Peacock Opal Mine. Love earthy textures? Boulder material from Australia offers similar rugged beauty, see our boulder opal pendant that lets matrix tones frame vibrant colour.
Bonanza Opal Mine
Another Virgin Valley gem, the Bonanza Opal Mine is open to the public from May through September for those in search of fire opals. Right next to the famous Virgin Valley Campground, it rents out several tools. Visit Bonanza Opal Mines for updates. For a subtle take on fiery play-of-colour, a timeless crystal opal pendant showcases shifting hues in a protective bezel.
State of Idaho
Opal ranks as the state's second-largest gem material value provider, making Idaho a noteworthy US opal supplier. White and pink valuable opals, as well as yellow, blue, and common opals, are all produced by the state.
Spencer Opal Mine
A significant supplier of opal, this is the biggest privately held gemstone mine in Idaho. Opalized wood and rare opal pieces have made this mine famous. At Spencer, you may find valuable opal that is commonly found filling gas voids in rhyolite-obsidian flows as thin layers within common opal. You may find both regular and rare pink opals in the Spencer Mine. More information at Spencer Opal Mines. Planning to set a Spencer find? Browse protective bezel-set opal ring designs ideal for everyday elegance.
Oregon
In particular, the opal formations of Morrow County's Opal Butte have brought Oregon international renown. Opal Butte has recently produced big, perfect opals, but Australia is the world leader in opal production. Rhyolite geodes, often called thundereggs, are common places to find opals in Oregon. See opal locality details from Mindat: Opal Butte.
Juniper Ridge Opal Mine
The fire opals found in this fee-digging mine in the Fremont-Winema National Forest are famous for their vibrant colours, which vary from red to orange to yellow. It is accessible seasonally, usually from the middle of June to the middle of October. Prefer a ready-to-wear statement? Explore shimmering blues in our boulder opal pendant for a durable, everyday style.
Arizona
Arizona features several opal deposits, particularly in volcanic regions. Its boundaries are home to many opal mines, one of which is the famous "Opal Hill Mine." This mine lets guests dig for opals; it's close to Gladdens Town. It provides a one-of-a-kind chance for novice and seasoned rockhounds to hunt for common and valuable opals. Explore Arizona occurrences via Mindat: Arizona opal. The "Royal Peacock Opal Mine" in Nevada, which is close to Arizona, is another great place to go if you're looking for high-quality opals. For a darker, dramatic palette akin to prized material, consider our sleek black opal ring.
New Mexico
Some parts of New Mexico's varied landscape are particularly abundant with opal deposits. Many rockhounds go to the "Bishop's Cap" mine because of the high-quality opals it produces. You should do your homework and get the appropriate permits before going opal hunting, as certain places may be privately held, but there are public grounds that you may hunt on. Key site: Rockhound State Park. See more at Mindat: New Mexico opal. Wearing opal daily? Read our practical guide to opal durability and everyday wear.
Wyoming
Regarding opal sites, Wyoming is yet another undiscovered treasure. Famous "Wyoming Opals," with their one-of-a-kind patterns and hues, are mined in the state. You should be ready for an adventure when you start out to explore, since the greatest spots generally demand a little hiking. A handy round-up of modern field spots is outlined in this Wyoming opal guide. If bold patterns appeal, a sculptural boulder opal ring echoes the rugged feel of field-collected specimens.
Conclusion
Whether you're an experienced rockhound or just starting out, searching for opals in the United States may be an exciting adventure. There are opal mining sites in every state, and each one promises a diverse variety of opals just waiting to be found. Make sure you research the rules and laws in your area about mining and collecting before you go on an expedition. You can also contact the mine owners to find out more about licences and costs. You may find your own opal gem if you're patient and enthusiastic. When it’s time to set a special find, our artisan-made opal ring and pendant designs turn field discoveries into heirloom pieces.