Idaho Rocks!: The Gem State While many of PSK members collect rock in Oregon, Washington, Nevada and northern California, Idaho also has a wide variety of rocks and gemstones and is a favorite place for rock hounds and mineral collectors. Because of Idaho’s natural beauty and many mountains, forests and streams, the pleasure of collecting is compounded and makes for memorable outings.
Unfortunately, for knappers, collecting rock of knappable size and quantity in Idaho is more of a challenge than in some other states. There are several obsidian sources in Idaho but most do not compare well with Oregon or California for size and variety of colors. Most Idaho Obsidian is black and many locations only have small quantities.
While visiting a museum in Moundsville, Ohio, an 8” obsidian blade was on display that was dug from the mounds there. The curator said that scientific analysis showed that the stone originated in eastern Idaho, not far from Yellowstone Park…on federal property that prohibits collecting.
On the other hand, from time to time, someone will make an extraordinary find. For example, a few years ago, someone found an absolutely beautiful light honey and dark brown, single piece of non-fractured common opal…more than 300 pounds in size! As I write this, I’m looking a 1 lb piece taken from a 30 lb opal nodule that also is absolutely beautiful. A friend gave it to me but will not divulge the source except to say that it was found somewhere between Plummer, Idaho and Coeur d’Alene. It is common to see small deposits of opal in road cuts and quarries but it has to be harvested before winter or it fractures into small pieces (which is why most opal points made my Native Americans in Idaho are usually no longer than an 1” long). If you’ve not tried it, opal is somewhat fragile but knaps easily. I like it.
I know where two pieces of common opal are that are huge…but one is high up on a vertical road cut and has been severely fractured by freezing. This 300 or so pound rock is fractured badly and it would be dangerous to try and collect it without risk of serious injury or death. I always stop and contemplate this rock when I make a trip down Highway 95 to Boise. Yes, I would like it but I’m not suicidal!
The other large piece of opal (400 lbs?) is embedded in the top center of a long railroad tunnel (35 feet above the rails). It would be absolute suicide (and illegal) to attempt to collect it. Also, what would you do if a train were to come through the tunnel while your digging partner was trying to pry the huge rock off your body?
I’m not aware of a large quarry of knappable rock that is easily accessed or is legal to collect from. A geologist told me of a fairly large agate deposit he found near Challis when a road was graded into a new mine but it’s on gated property and he would not tell me the precise location. It was blue/green in color. Yes, I really tried to get a bunch of that. This is Idaho; Rock is where you find it.
Some really nice agate occasionally shows up in rock shops and originates on both private and public property not too far from Boise. I was told that some particularly nice rock came from “Secret Mountain” which is near “No-Name Creek.” I’m not sure where that is but Succor Creek and other areas in the Owyhee Desert in both Idaho and Oregon have a wide variety of great rock there. Just remember that the Owyhee is 6 million square acres in size and is the last and largest hardly-populated area in the continental USA. Part of my pickup truck is stuck on a rock on one of the roads into that area and if it rains, you may have to camp out until the gumbo-mud-roads dry out.. If you don’t like to see other people and don’t mind flat tires, the Owyhee may be just the ticket for you. By the way, my truck’s GPS “got lost” here. Occasionally, malcontents hide out in the Owyhees so a side arm may give you some comfort, as well as extra food, sleeping bag and a tent in the event Mother Nature chooses to keep you longer than you planned.
Idaho has various steep road grades cut from rock. I’ve heard that some have found some knappable rock in the rip-rap on the downhill side from the highways but collecting in these places may be illegal, if not dangerous. Idaho has a lot of vertical territory.
From time to time knapper friends and I have collected large pieces of native agate (one 375 lbs) but what we found was not of the best of quality and usually fractures upon heat treating. Obsidian is found in several locations on southern and central Idaho but the nodules tend to be baseball-size, on average. Larger pieces are probably available but, if so, are closely held secrets. Of course, the Gem State has a plethora of smaller, jewelry-quality gemstones such as fire opal, star rubies, amethyst, petrified wood, quartz, citrine, jasper, many varieties of agate, geodes, and even some sapphires. Of course, the internationally famous garnet diggings on Emerald Creek (near Clarkia) give collectors an opportunity to find gem and star garnets in remarkably large sizes and quantities. I’ve seen garnets almost the size of baseballs but have never seen any that would be knappable. If you are lucky enough to find several 6-ray star garnets, they might help pay for the pickup truck you trashed in the Owyhees. http://www.spokesman.com/stories/2009/may/03/garnet-digs-secret-jewel-central-idaho/
For more detail on the general location of Idaho rocks go to the state’s web site for rock hounds at https://www.idl.idaho.gov/mining/rockhounding/ . For specific locations, it’s advisable to join one of the various rock hound groups and go on field trips with them. If you do this, you must keep in mind that their primary purpose is to collect relatively small stones for jewelry.