Precious opal is a rare and exotic gemstone that is primarily found in Australia. Ninety-five per cent of the world's opal supply is mined in Australia, but this prized stone is found in Nevada as well. In its natural state, opal is considered "raw" or "rough." In America, you can find raw opals in the Virgin Valley district of Nevada. Prospectors in this area have uncovered fire opals, crystal opals, wood opals, white opals and black opals, which are Nevada's state precious gemstone. For those who lack the time and resources to purchase a private claim from the government, anyone can mine Virgin Valley by paying a fee to existing claim owners.
Contact a claim owner in Virgin Valley who provides fee-digging that is open to the general public. The most well-known mines are the Royal Peacock Opal Mine, Bonanza Opal Mine LLC, The Opal Queen Mine and Rainbow Ridge Opal Mine. Evaluate these claims by price, accessibility, accommodations and any evidence you can find that suggests you will have a lucrative dig. (See links in Resources.)
Plan your trip. Make reservations for accommodations if necessary. Mining is open to the public from May through October. The fee-digging sites allow camping for a small fee, usually under £6. RV hookups are available and typically cost under £26. There are also motels available in nearby Denio. The cost of mining for raw opals is £97 to £130 per day. You can also dig in the tailings and mine dump area for under £65 per day.
Choose a bank at the site that you feel will be promising. The claim owners have worked diligently in the off season to expose sloping, vertical banks and terraces that contain the opal-filled silica. Use a pick or rock hammer to knock material free from the bank. Try to knock about a handful off at a time. Work evenly across the bank to avoid undercutting, which can lead to dangerous rockfall conditions. Work on top of your kneeling pad to protect your knees. Gather and organise loose material with a shovel.
Examine the material you have removed from the bank. Use your blade, rock hammer, screwdriver and pick to break the chunks into smaller pieces and keep a close eye out for opal. Raw opal has a waxy appearance with fresh-chipped edges. It is noticeably different in colour and texture from the surrounding rocks. Experienced rock hounds suggest that even a novice can easily spot an opal. Continue to break off handfuls of material from the bank and inspect it for opals. Use gloves when handling the rocks to avoid injury.
Store the opal specimens you find in a bucket. Use hand tools to break away excess material and fully extract the gemstone. Remove most of the excess but don't get too critical, as you can exact the process at home. The key here is to make the specimen carryable. You may want to store the opal in water. Rapid drying can cause cracking and crazing, which can drive down the price of the gemstone. Water will prevent this, but in some types of opal where wood is present, water can cause the wood to expand and crack the opal. On-site staff at the claim can inform you which type you have and whether or not water is appropriate.
Listen as you mine. The sound of hitting glass is often the first indicator that you have found raw opal.
Make sure to break off materials evenly across the bank to avoid creating dangerous conditions. The Nevada desert is extremely hot, and miners have suffered heat exhaustion. Be sure to have an ample supply of water and don't overdo it.