Red Cloud Mine
The Silver District claim that set the standard for wulfenite: thick orange-red tablets, the Ed Over legend, and a locality label that gets borrowed.
The Red Cloud Mine in the Silver District of La Paz County, Arizona is the benchmark wulfenite locality. Red Cloud crystals are thick orange-red tablets, the finest over 5 cm, coloured by trace chromium. Lead and silver were mined here through the 1880s; Ed Over's 1938 dig made the Red Cloud a collector name.
In short
- The Red Cloud is a patented claim in the Trigo Mountains, roughly 50 miles north of Yuma. It is private ground — there is no public collecting.
- The wulfenite is PbMoO4, hardness 3, in thick square tablets. The deep red is attributed to trace chromium carried in from the monzonite footwall.
- Three specimen eras set the market: the 1880s lead-silver workings, Ed Over in 1938, and the open-cut programme from 1996.
- Crystals sit on a pale altered vein matrix with barite, fluorite and oxidised galena. Damage lives on corners and edges, never the faces.
- Red Cloud is one of the most borrowed labels in the trade. Arizona has a dozen other wulfenite mines and their material gets relabelled upward.
| Locality | Typical colour | Habit | Note |
|---|---|---|---|
| Red Cloud, La Paz Co., Arizona | Deep orange-red | Thick square tablets | The benchmark; chromium-coloured |
| Erupción/Ahumada, Los Lamentos, Chihuahua | Butterscotch to orange | Tabular to steeply bipyramidal | Largest fine crystals, documented above 6 cm |
| Rowley mine, Maricopa Co., Arizona | Orange | Tablets, often with mimetite | Best known for wulfenite–mimetite combinations |
| Glove mine, Santa Cruz Co., Arizona | Orange to brown-orange | Thin tablets, small | Sharp but rarely large |
| Old Yuma mine, Pima Co., Arizona | Orange to red | Blocky | Historic Tucson-area material |
| Bad Bleiberg, Carinthia, Austria | Yellow to grey | Thin tablets | Type locality; species named 1845 |
| Tsumeb, Namibia | Yellow to orange | Blocky, often on cerussite | Old-collection material only |
| Mibladen, Morocco | Yellow-orange | Small tablets on barite | Usually alongside vanadinite |
Where the Red Cloud is, and what the vein is
The Red Cloud sits in the Silver District of the Trigo Mountains, La Paz County, in the arid southwest corner of Arizona, about 50 miles north of Yuma. The workings follow a fault-controlled vein — quartz with barite and fluorite — cutting volcanic and intrusive rock, and the ore was silver-bearing galena. Everything the collector cares about happened afterwards, in the oxidised zone above that galena.
Wulfenite is lead molybdate, and it needs three things at once: lead from the primary ore, molybdenum leached in from somewhere, and an oxidising near-surface environment. Plenty of lead mines have the first and third and no wulfenite at all. The Red Cloud had all three, and one more ingredient that almost nowhere else did.
That fourth ingredient is chromium. The deep orange-red of Red Cloud wulfenite is attributed to trace chromium — the chromate ion acting as a chromophore — understood to have been carried in solution from the monzonite forming the footwall of the vein as groundwater percolated down through the oxidising orebody. Most of the world's wulfenite is yellow to honey-orange. This one is red, and the explanation is local geology rather than anything the crystals do differently.
1880s silver, 1938 Ed Over, 1996 open cut
The Red Cloud began as an open cut in the 1860s and 1870s and produced lead and silver through the 1880s. By 1890 the underground workings had reached broadly the extent they hold today. The dumps were reworked in 1949 for the silver still in them, and the property then went quiet as a commercial mine.
Specimen history runs on a separate track. Fine wulfenite was known from the first period of mining, but the locality's reputation was made by Ed Over in 1938, working underground effectively alone with hand tools and recovering crystals exceeding two inches. Over-era material is a distinct thing in the market: a specimen with documented 1930s provenance trades differently from a modern piece of equal quality, and it is one of the few places in mineral collecting where the paperwork genuinely is part of the object.
The third era began in 1995, when a group headed by Wayne Thompson obtained clear ownership of the patented claim. Systematic work started in January 1996, stripping the vein from surface rather than stoping it underground, and in the spring of that year opened a crystal-lined vein cavity around 10 cm wide and roughly one metre by four across — the source of a great deal of the good material that reached collectors in the following years.
We do not put a closure date on the Red Cloud. The claim has stayed in private hands, production has come in bursts rather than continuously, and most of what changes hands now is recirculating out of collections rather than coming out of the ground.
Grading a Red Cloud wulfenite
Colour comes first. The premium is for a saturated orange-red that holds its depth when light passes through the tablet, rather than a thin orange that goes pale at the edge. Then lustre: Red Cloud faces should be bright and slightly resinous to almost metallic in raking light, and a dull face usually means surface etching or a cleaned-off coating.
Then condition, and here the habit works against you. A thick square tablet standing proud of the matrix presents four edges and four corners to the world, and corner chips are the commonest defect on the market by a wide margin. Examine edges under a lens rather than faces — a chip reads as a bright fresh surface against the slight sheen everywhere else.
Then composition of the piece: how many crystals, whether they stand free or lie flat, whether the largest is undamaged and well placed, and whether the matrix is proportionate. A single perfect 3 cm tablet centrally placed on a small plate beats a crowded plate of damaged 4 cm tablets.
Repairs and reattachments are common on important specimens and, disclosed, are normal practice. The giveaways are a hairline of adhesive where crystal meets matrix, a gap under one edge, or a crystal orientated differently from everything else on the plate.
The label problem
Arizona is full of wulfenite. Rowley, Glove, Old Yuma, Defiance, Hilltop, Tiger and others all produced it, and Los Lamentos and the San Francisco mine did the same across the border in Mexico. Red Cloud is the name that commands the most, which creates a permanent one-way pressure on labels: material drifts upward toward the famous locality and never downward.
What protects you is consistency. Red Cloud wulfenite has a characteristic combination — thick tabular habit, deep red-orange, that particular lustre, and a pale altered vein matrix with barite and fluorite — and a piece that departs from it in two or three respects deserves a question. Ask what the dealer's source was, whether there is an old label, and which era the piece is thought to belong to. A dealer who knows Red Cloud can answer all three; a dealer who cannot is passing on someone else's guess.
Old labels are worth real money here for exactly this reason, and are the reason we cover buying old collection material as a subject in its own right.
Light, storage and access
Collectors keep Red Cloud wulfenite out of direct sunlight, and some report that the colour fades with prolonged exposure. We have not seen a controlled demonstration either way, so we treat it as a precaution rather than a fact — but it is a precaution that costs nothing. A cabinet away from a south-facing window, or a drawer, removes the question.
The certain risks are duller. Hardness 3 means anything harder in the same drawer will scratch it. Brittle tablets do not survive being slid across a shelf. And it is a lead mineral, so no sawing, no grinding, no dry brushing, and wash your hands.
On access: the Red Cloud is a privately held patented claim and is posted. It is not a locality you can go and collect at, and the specimen route is the market rather than the field.