Hoag Mining District – Modoc County, California
You can drive to pretty much any open cut/trench on the claim.
This claim is located on an easy high clearance 2WD road.
Contact us for exact coordinates

The mine is known for its specific strain of obsidian. Since the early 1960s it has produced "rainbow" and a particularly deep purple color, for which the mine was named. The obsidian is highly prized for its gem quality and color. The mine is quite old but has been intermittently worked through the 1970s. The surveyors reported "more obsidian than you could load in a year". The mine is set in a deeply forested area. The obsidian from this deposit is well known and highly valuable for jewelry. This claim is easy to get to on 2WD roads in excellent condition. This property could be used for a pay dig site, as it has been in the past. There is a substantial amount that could be recovered just from the ground. The rainbow obsidian is going to be the crown jewel recovery and is quite expensive. True rainbow obsidian averages $20-25 per pound uncut. Larger samples and boulders go for substantially more. A 65 lb chunk of obsidian was dug out of this property in 2015, rounded into a ball and polished for a water feature, the piece sold for $15,000.

This district is an area of eruptive rocks composed of rhyolite, quartz-andesite or dacite, andesite and basalt, occupying the summit of the Warner mountains, a mountain range varying in altitude from 6,000 to 9,000 ft., extending south from Oregon for Some 60 miles into California, from which state they pass into Nevada. In California these mountains run a little east of south and separate Goose Lake valley on the west from Surprise valley on the east. The volcanic formation has been thrust through the flat, basaltic flows and make an “island” of eruptive rocks in a “sea” of basalt.

The eruptions forming this island vary from the most acidic to a very basic one. No direct evidence, further than that of inclusions, was observed to fix the relative age of these rocks, but the basalt dikes are probably the oldest and Were followed successively by the andesite, dacite and rhyolite.

The basalt occurs as dikes in the Southern end of the district and comprises about one-eighth of the total area. It is a fine-grained rock, not much altered, showing long, lath-shaped crystals of augite in a ground-mass of a mixture of that same mineral, with a basic feldspar. Toward the north edges of this basalt Were found some hand specimens which showed quartz phenocrysts, very much corroded. In the wash from this area are found rocks, the originals of which were sandstones, although they are now thoroughly metamorphosed. Their presence can only be accounted for by their having been broken from the rocks through which this basalt has passed and been brought up as inclusions. Later erosion exposed and liberated them.[1]

There is a good history of the deposit and the workings. From Desert Magazine, in 1972:

Over the years, one location, the Royal Purple Mine, has continued to produce top quality obsidian in various shades of purple, blue, green, gold and silver sheen and the coveted "rainbow type." Mining began 14 years ago and, though tons of material have been removed, the tremendous deposits have barely been dented. It seems safe to say that future generations of rockhounds will also enjoy collecting and working this fine gem material.

The obsidian is obtained by the open-pit method of mining. A 3 1/2 to 4 1/2 pound pick, a shovel and gloves are the tools required. The size of the specimens range from one-quarter pound up to 500 pound boulders. However, the average size runs two to eight pounds. A fee of $3.00 is charged and allows the collector 20 pounds of material. All over this weight is 15 cents a pound.

The Royal Purple Mine consists of eight claims and is owned by Ray and Sue Griffith of Quartzsite, Arizona. Jack and Marie Williams will be managing the mine during the 1972 season.

Fifteen years ago, obsidian hadn't as yet become a popular cutting material. The snowflake type (Utah) was being used but most of the obsidian available was black, smoky-clear or with layered and cloud patterns. Its use was limited.

The Griffiths were long-time and avid rock collectors when in 1957, on a vacation trip through Utah, they were shown a specimen of rainbow obsidian. The beauty of the material intrigued Ray and his efforts to learn more about it boiled down to "it comes from Northern California."

As their vacation progressed, Ray kept inquiring about the obsidian wherever they stopped. It was in a most unlikely place, the California Inspection Station north of Alturas, that his inquiries at last bore fruit. He was told the material came from the Warner Mountains northeast of Davis Creek. Ray spent the next six days prospecting the area and located what was to become the Royal Purple Mine.

The spring of 1958 found the Griffiths busy developing their obsidian deposit. It was opened to collectors that year and when outstanding specimens began to appear in displays its popularity rapidly began to rise.[1]

Access to the Mine: You can drive to pretty much any open cut/trench on the claim.
Tailings Present: No tailings or waste dump on site. Trenches and pits have been dug around the area where obsidian is found. The only waste is dirt.
Entrance: Open pits and trenches.
Mine Cut: Trench
Depth / Length: Over 4 acres of existing pits.
Minerals in the Mine: Obsidian everywhere. Various grades and various colors. Mostly black and dark purple obsidian.
Foot Traffic in the Mine: Moderate
Last Worked: 1979

Federally Registered Mining Claim ID: CAMC0313095