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Molybdate · Anhydrous molybdate (scheelite structure) · Scheelite Group

Wulfenite

PbMoO₄

Thin orange wafers of lead molybdate — so dense they feel like metal, so delicate they chip if you look at them wrong.

Hardness2.5–3
Crystal systemTetragonal
LusterAdamantine
Sp. gravity6.5–7
ClassMolybdate
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Wulfenite specimen

Wulfenite — thin orange tabular crystals, the 'yellow lead ore' of classic lead districts — Photo: Ivar Leidus · CC BY-SA 4.0

What is Wulfenite?

Wulfenite is lead molybdate — PbMoO₄ — a mineral of contradictions. It is one of the densest bright minerals you can hold (it is mostly lead), yet it forms plates so thin and brittle that collecting one undamaged is an achievement.

It belongs to the scheelite family: the same tetragonal atomic pattern as scheelite (calcium tungstate) and powellite (calcium molybdate), but with lead swapped in — which is what turns the color up to orange and the density up to nearly seven times that of water.

Miners knew it as 'yellow lead ore'; mineralogists named it for Franz von Wulfen, the Austrian Jesuit who catalogued the minerals of Carinthia. Today it is a crown jewel of collections — Arizona's Red Cloud Mine has been worked almost entirely for cabinet specimens.

In one sentence: Wulfenite forms thin square orange plates, is denser than lead ore has any right to be, and is soft and fragile enough to scratch with a fingernail's edge.

Physical Properties

The full data table is in the panel alongside. Here’s what those numbers actually mean.

Habit. The signature look: wafer-thin square or rectangular tablets, often with beveled edges, sitting on matrix like panes of orange glass. Thicker crystals go pyramidal; massive material is just 'yellow lead ore'.

Density and softness together. SG ~6.5–7 with Mohs 2.5–3 — heavy and fragile, a combination produced by lead-rich chemistry in an open structure.

Color. Yellow-orange through deep red-orange, adamantine to resinous. The color is intrinsic to the Pb–Mo–O structure.

No glow. Unlike its cousin scheelite (bright blue-white under UV), wulfenite does not fluoresce — a handy separating test.

How & Where It Forms

Wulfenite is a secondary mineral, crystallizing in the oxidized zone where primary lead sulfides and molybdenum minerals (often molybdenite) weather together. Oxygen-rich desert groundwater does the combining: lead plus molybdate in, thin orange plates out.

The great localities are all dry-country oxidized lead districts — Arizona's Red Cloud and Rowley mines, Mexico's Los Lamentos, Tsumeb's deep oxide zone, and the type locality at Bleiberg in Austria.

Often grows alongside:

VanadiniteMimetiteCerussiteAnglesiteDescloiziteHemimorphiteCalciteQuartzGoethitePyromorphite

What It’s Used For

Molybdenum oreA minor ore of molybdenum — the metal that hardens tool steels — though molybdenite supplies most of the market.
Collector specimensThin orange plates from Arizona and Mexico are among the most sought-after secondary minerals; whole mines have been worked just for specimens.
Gemstones (rare)Occasionally faceted for collectors — beautiful but far too soft and fragile for jewelry.

How to Identify It

Thin square orange plates + lead-weight heft + softness is nearly unique. If it glows under UV, suspect powellite or stolzite; if it forms hexagonal prisms instead of square wafers, it is vanadinite.

Thin square or beveled orange plates — the habit is nearly uniqueVery dense (SG ~6.5–7) yet soft and fragileAdamantine sparkle on the plate facesWhite streak; a fingernail almost scratches it
Looks like…But differs because…Quick test
StolziteLead tungstate — same family and look, usually duller and browner; fluoresces under UVUV lamp
PowelliteCalcium molybdate — lighter, typically brownish, fluoresces cream to yellowUV lamp & heft
VanadiniteSix-sided prisms and barrels, not thin square wafersCrystal form
CrocoiteBrighter red-orange but long slender striated needlesCrystal form
MimetiteRounded barrel crystals ('campylite'), never flat platesCrystal form

Where It’s Found

Notable localities for fine specimens:

Red Cloud Mine, USA Bleiberg, Austria Rowley Mine, USA Erupción Mine (Ahumada), Mexico Tsumeb Mine, Namibia Touissit, MoroccoOpen the locality map →

References & Further Reading

  1. Dana's New Mineralogy, 8th ed. Molybdates and tungstates, scheelite group.
  2. Mindat.org — Wulfenite mineral data and locality records.
  3. Wikipedia — Wulfenite.

Last reviewed 2026-09-14 · How to cite this page.