Short answer: wulfenite is lead molybdate, PbMoO4, a soft and very heavy mineral best known for thin, square, orange to yellow plates stacked like cards in cavities of weathered lead ore. Arizona's Red Cloud Mine produced the reddest classics, and it became Arizona's state mineral in 2017. Most affordable specimens today come from Mexico, China and Morocco. Treat it as a fragile lead mineral: hold the matrix, wash your hands, no water soaking.
Why do wulfenite crystals grow as thin square plates?
Plates are the signature. Minerals.net describes the usual habit as thin tabular crystals with a square or octagonal outline and a very narrow mid-section, often flaky, fragile and grouped in platy aggregates (Minerals.net). Less often wulfenite grows as long bipyramids or thick, almost cube-like blocks, and those chunky crystals come from specific deposits such as Villa Ahumada in Chihuahua.
The square outline reflects the crystal structure. Webmineral classifies wulfenite as tetragonal, dipyramidal class, space group I41/a, and places it in a series with stolzite, PbWO4, in which tungsten takes the place of molybdenum (webmineral). To the eye, that symmetry is the four-sided tablet collectors know.
A thin plate is the most fragile shape a crystal can take. A wulfenite blade only a millimeter or two thick at hardness 3 snaps with a light knock, which is why so many specimens arrive with a broken corner and why packing matters more for wulfenite than for almost any other common collector mineral.
What are wulfenite's key properties?
| Property | Value |
|---|---|
| Formula | PbMoO4 (lead molybdate) |
| Composition | Pb 56.44%, Mo 26.13%, O 17.43% |
| Crystal system | Tetragonal |
| Mohs hardness | 3 |
| Specific gravity | 6.5 to 7 (average 6.75) |
| Streak | White to yellowish white |
| Luster | Adamantine to resinous |
| Fluorescence | Sometimes yellow to orange to red under UV |
The composition line comes from webmineral's calculation: lead makes up 56.44% of the weight and molybdenum 26.13%. That makes wulfenite less lead-rich than vanadinite, but still more than half lead by weight, and heavy enough that a 2 cm plate feels oddly dense.
The name honors the Austrian mineralogist Franz Xaver von Wulfen (1728 to 1805). The type locality is Bleiberg in Carinthia, Austria, with a pre-IMA species date of 1845 according to webmineral.
Does wulfenite glow under UV?
Sometimes. Minerals.net notes that wulfenite is occasionally fluorescent dark yellow or orange in shortwave UV and dark orange to red in longwave, while webmineral records yellow to orange to red under both. Many specimens show little or nothing, so a dull result under a lamp proves nothing either way. It is still a useful contrast with vanadinite, which webmineral lists as non-fluorescent.
Where does the best wulfenite come from?
Wulfenite is a secondary mineral of oxidized lead deposits. It forms where weathering breaks down primary lead ore such as galena and molybdenum is available in the same groundwater. Minerals.net lists calcite, limonite, barite, mimetite, vanadinite, pyromorphite, cerussite and descloizite among its usual companions.
The key localities, by what they produce:
| Locality | What the material looks like |
|---|---|
| Red Cloud Mine, Trigo Mountains, La Paz County, Arizona | Bright reddish-orange plates, the benchmark color |
| Rowley Mine, near Theba, Maricopa County, Arizona | Tabular orange-yellow crystals |
| Glove Mine, Santa Cruz County, Arizona | Large platy crystals |
| 79 Mine, Hayden, Gila County, Arizona | Glassy, gemmy crystals |
| Villa Ahumada, Los Lamentos, Chihuahua, Mexico | Thick, blocky crystals |
| San Francisco Mine, Sonora, Mexico | Thin transparent yellow crystals |
| Bleiberg, Austria (type locality) | Thin orange octagonal crystals |
| Jianshan Mine, Xinjiang, China | Brilliant thin plates |
| Chah-Kharboze Mine, Anarak, Iran | Blood-red crystals |
| Mibladen and Touissit, Morocco | Thin, platy clusters |
All of the descriptions in that table come from the Minerals.net locality list, which also states that the bulk of collector specimens come from northern Mexico and the southwestern United States, and that virtually all notable US wulfenite localities are in Arizona (Minerals.net).
Chinese material on today's market also includes plates labeled from the Maoniuping area of Sichuan, typically small yellow to orange tablets scattered over a gray or brown rock matrix. Moroccan wulfenite tends to be small too, often micro plates from the same districts that supply vanadinite; see our Morocco origin guide.
Why is wulfenite Arizona's state mineral?
Arizona made it official in 2017. House Bill 2092 added section 41-860.04 to the Arizona Revised Statutes, which reads simply that wulfenite is the official state mineral; the governor approved it on March 22, 2017 (Arizona Legislature).
The push came from a geologist. Arizona Public Media reported that University of Arizona geologist Alexander Schauss was surprised to find the state had no designated mineral, and that, in his words, the best specimens came from mines in Pima, La Paz, Maricopa and Gila counties (AZPM). Wulfenite joined copper (state metal), turquoise (state gem) and petrified wood (state fossil). The Paleontological Research Institution's Earth@Home summary of Arizona symbols records the same 2017 date (Earth@Home).
How fragile is wulfenite, and is it toxic?
Two separate questions, and both deserve a straight answer.
Fragility. At hardness 3 with imperfect cleavage and brittle fracture, wulfenite is easily chipped. Plates standing on edge are the weak point. Lift a specimen by the base, never by a crystal, and do not let a brush or cloth catch a plate edge. Store each piece in its own padded box; loose wulfenite rattling in a drawer destroys itself.
Lead content. Wulfenite is more than half lead by weight. The University of Cambridge's Museum of Archaeology and Anthropology advises that powdery, flaking or loose heavy-metal materials warrant the most care, while stable surfaces are generally safe to handle with disposable gloves alone (MAA Cambridge). For a home collection that means: handle intact specimens briefly, avoid making dust or crumbs, keep pieces away from food and young children, wash your hands after handling, and never use wulfenite in water for drinking or bathing. The full method is in our toxic minerals handling guide.
Cleaning is mostly a no. Dust with an air blower. A quick rinse of plain water on a sturdy matrix piece is acceptable, but avoid acids and ultrasonic cleaners, which can loosen thin plates from their base.
What is wulfenite used for, and what does tradition say?
Wulfenite is a minor ore of lead and molybdenum. Molybdenum is used principally as an alloying agent in steel, cast iron and superalloys to improve hardenability, strength, toughness and corrosion resistance, according to the U.S. Geological Survey (USGS). Commercial molybdenum comes overwhelmingly from molybdenite, not from wulfenite, so collector specimens are a side product of small lead workings and hand digging.
In crystal traditions, wulfenite is associated with creativity and with bringing ideas into form, a link people draw from its bright color and flat, geometric crystals. Those associations are cultural, not mineralogical.
What makes one wulfenite worth more than another?
- Color. Red and red-orange (Red Cloud style) command the highest prices; yellow and honey colors cost less.
- Plate size and thinness with intact edges. Large, thin, undamaged plates are hard to extract and harder to ship.
- Arrangement. Plates standing up from the matrix at angles, with daylight between them, display best.
- Locality. Classic Arizona localities carry a premium over newer Chinese and Moroccan finds of similar quality.
- Damage and repair. Ask whether any plate was reattached. Under a loupe, glue shows as a shiny line or a slight gap where a plate meets the matrix.
Choosing a wulfenite specimen from our stock
Our current wulfenite covers three price points, two localities and two sizes, which makes it easy to compare what money buys.
- Micro Wulfenite Crystal Cluster: three Moroccan micro clusters on a 1.25 inch acrylic square, 12 g total. Small plates already mounted, ideal under a 10x loupe and protected from fingers.
- Wulfenite Cluster on Matrix from Maoniuping Mine, Sichuan, China: 2.5 x 1.25 x 2 inches, 79 g, a compact matrix piece that shows how plates scatter across the host rock.
- Wulfenite Cluster on Matrix from Maoniuping Mine, Sichuan, China (larger piece): 3 x 2 x 2.25 inches and 98 g, more matrix and more plates for a shelf display.
When comparing listings, check that the locality is named, that dimensions and weight are given, and that the photos show the front plates close enough to judge their edges.
Digital Towns Market
Wulfenite in stock
Frequently asked questions
Is wulfenite rare?
As a species it is uncommon, found mainly in oxidized lead deposits in arid regions. Small plates on matrix are affordable because Mexico, China and Morocco supply them steadily. Large, red, undamaged plates from classic Arizona localities are genuinely scarce and priced accordingly.
Is wulfenite safe to keep at home?
Yes, with sensible habits. It is a lead mineral, so keep it in a cabinet or box, handle it by the matrix, avoid making dust, wash hands afterwards and keep it away from children, pets and food. Never put it in drinking water or use it for elixirs.
What is the difference between wulfenite and stolzite?
They form a series. Wulfenite is lead molybdate and stolzite is lead tungstate, with tungsten replacing molybdenum. Stolzite is rarer, usually lighter in color and found at different localities. Tungsten-rich intermediate material is sometimes called chillagite.
Can orange barite be mistaken for wulfenite?
Occasionally. Tabular orange barite can look similar, but it is far lighter in the hand, with a specific gravity of 4.3 to 4.6 instead of about 6.75, it usually comes from different localities, and its color is rarely as vivid.
Why are so many wulfenite plates broken?
The crystals are thin plates of a hardness 3 mineral, so extraction, trimming and shipping all cause damage. A specimen with every plate intact is worth noticeably more, and honest listings disclose chips and repairs.
Sources
- Minerals.net, Wulfenite: https://www.minerals.net/mineral/wulfenite.aspx
- webmineral, Wulfenite Mineral Data: http://webmineral.com/data/Wulfenite.shtml
- Arizona Legislature, Chapter 45, House Bill 2092 (2017): https://www.azleg.gov/legtext/53leg/1r/laws/0045.htm
- Arizona Public Media, Wulfenite Joins Other State Symbols as Official Mineral: https://azpm.org/s/47955-wulfenite-confirmed-as-state-mineral/
- Paleontological Research Institution, Earth@Home, Arizona Earth Science Quick Facts: https://earthathome.org/?p=12731
- Museum of Archaeology and Anthropology, University of Cambridge, Heavy metals: https://maa.cam.ac.uk/heavy-metals
- U.S. Geological Survey, Molybdenum Statistics and Information: https://www.usgs.gov/centers/national-minerals-information-center/molybdenum-statistics-and-information
- Minerals.net, Barite: https://www.minerals.net/mineral/barite.aspx