Is wulfenite an oxide?
Is wulfenite an oxide? No: wulfenite, Pb(MoO4), is a lead molybdate in both the Dana and Strunz schemes, although 17.43% of its mass is oxygen. A mineral? Yes.
No. Wulfenite, Pb(MoO4) on the IMA list, is a lead molybdate: Dana class 48, anhydrous molybdates and tungstates, and Strunz 07.GA.05, among the molybdates, as webmineral prints them. Oxygen is 17.43% of its mass, more than in the lead oxide plattnerite (13.38%) or cuprite (11.18%), so oxygen content alone does not make a mineral an oxide.
In short
- The verdict. Wulfenite is a molybdate, not an oxide. The September 2026 IMA-CNMNC Master List writes it Pb(MoO4), with the molybdenum and its four oxygens as one bracketed group, as it writes Pb(SO4) for anglesite and Ca(CO3) for calcite. The webmineral wulfenite page gives Dana 48.01.03.01 (anhydrous molybdates and tungstates) and Strunz 07.GA.05 (molybdates, wolframates and niobates).
- The class ledger: oxygen does not decide. Worked on standard atomic weights, wulfenite is 56.44% lead, 26.13% molybdenum and 17.43% oxygen. The lead oxide plattnerite, PbO2, is 13.38% oxygen and cuprite, Cu2O, 11.18%: both less, and both filed as oxides, Dana 04 and Strunz 04. Metal to oxygen is 1:2 in wulfenite and in plattnerite alike.
- Documented failure: the tungstates split. On webmineral, Dana keeps wulfenite, stolzite, scheelite, powellite, ferberite and hübnerite together in class 48. Strunz puts the first four in 07.GA.05 but files ferberite and hübnerite at 04.DB.30, among the oxides, in a group described as chains of edge-sharing octahedra. So whether a tungstate is an oxide depends on the scheme; for wulfenite both say molybdate.
- Oxide columns are bookkeeping. The Handbook sheet prints the Oudida, Morocco, analysis as MoO3 38.87 and PbO 60.91, corresponding to Pb1.01Mo1.00O4.00. Webmineral’s own panel tabulates wulfenite as MoO3 39.21 and PbO2 65.15, a total of 104.36%. Writing an analysis as oxides is a way of counting the elements, not a classification.
- Is wulfenite a mineral? Yes: it has its own IMA row, status G, 1845, Austria. The Handbook of Mineralogy sheet gives tetragonal, hardness 2.75 to 3, density 6.5 to 7.5, streak white, and calls it a secondary mineral of the oxidized zone of hydrothermal lead deposits.
| Mineral | IMA formula | Oxygen by mass | Metal : oxygen | Dana class (webmineral) | Strunz class (webmineral) | An oxide? |
|---|---|---|---|---|---|---|
| Wulfenite | Pb(MoO4) | 17.43% | 1 : 2 | 48.01.03.01, anhydrous molybdates and tungstates | 07.GA.05, molybdates, wolframates and niobates | No, in both |
| Stolzite | Pb(WO4) | 14.06% | 1 : 2 | 48.01.03.02 | 07.GA.05 | No, in both |
| Powellite | Ca(MoO4) | 31.99% | 1 : 2 | 48.01.02.02 | 07.GA.05 | No, in both |
| Scheelite | Ca(WO4) | 22.23% | 1 : 2 | 48.01.02.01 | 07.GA.05 | No, in both |
| Ferberite | Fe2+(WO4) | 21.07% | 1 : 2 | 48.01.01.02 | 04.DB.30, oxides | Strunz yes, Dana no |
| Hübnerite | Mn2+(WO4) | 21.14% | 1 : 2 | 48.01.01.01 | 04.DB.30, oxides | Strunz yes, Dana no |
| Plattnerite | PbO2 | 13.38% | 1 : 2 | 04.04.01.06, simple oxides | 04.DB.05, oxides | Yes, in both |
| Cuprite | Cu2O | 11.18% | 2 : 1 | 04.01.01.01, simple oxides | 04.AA.10, oxides | Yes, in both |
What class of mineral is wulfenite?
A molybdate, in both of the schemes collectors meet. The webmineral wulfenite page gives Dana class 48.01.03.01, in class 48, anhydrous molybdates and tungstates, beside stolzite at 48.01.03.02. It gives Strunz 07.GA.05: class 07, headed sulfates (selenates, tellurates), subclass 07.G, molybdates, wolframates and niobates, group 07.GA, without additional anions or H2O. In the Strunz scheme the molybdates sit in the same class as the sulfates; in Dana they have a class of their own. Neither files wulfenite with the oxides.
What the words mean. An Introduction to Geology (Johnson and others, 2017), chapter 3 says oxides consist of metal ions covalently bonded with oxygen, and describes many non-silicate minerals as salts, compounds made by replacing the hydrogen in natural acids: carbonate minerals are salts built around the carbonate ion, and sulfate minerals contain a metal ion bonded to a sulfate ion. The IMA list writes wulfenite Pb(MoO4), the molybdenum and its four oxygens bracketed as one group, in the way it writes Pb(SO4) for anglesite and Ca(CO3) for calcite. The same kind of class question is worked for calcite on is calcite a silicate and for sylvite on is sylvite a halide.
Wulfenite has oxygen in it. Why is it not an oxide?
The class ledger. Worked from the IMA formulas on standard atomic weights, wulfenite, PbMoO4 (367.15), is 56.44% lead, 26.13% molybdenum and 17.43% oxygen, the figures webmineral prints and those on is wulfenite radioactive. Two minerals on this site that both schemes file as oxides carry less: plattnerite, PbO2, 13.38% oxygen, and cuprite, Cu2O, 11.18%. Powellite, Ca(MoO4), is 31.99% oxygen and still a molybdate. The share of oxygen is not the test.
Nor is the ratio. Counting every metal atom against oxygen, wulfenite is 2 to 4, or 1:2, and so is plattnerite, PbO2, which Strunz files in subclass 04.D, “Metal:Oxygen = 1:2 and similar”. The same count gives 1:2 for every molybdate and tungstate in the table. Neither number decides; the class codes in the table are the two schemes’ own filing, as webmineral prints them.
Neighbours on the sheet. The Handbook wulfenite sheet names its associates as cerussite, anglesite, smithsonite, hemimorphite, vanadinite, pyromorphite, mimetite, descloizite, plattnerite and Fe–Mn oxides. A specimen of wulfenite on plattnerite is a molybdate on an oxide: two classes on one piece.
Are any tungstates or molybdates classed as oxides?
Yes, in Strunz: ferberite and hübnerite. Webmineral gives both ferberite and hübnerite the Strunz code 04.DB.30, in class 04, oxides, subclass 04.D, metal:oxygen 1:2 and similar, group 04.DB, described as with medium-sized cations and chains of edge-sharing octahedra. Plattnerite is in the same group at 04.DB.05. Dana keeps ferberite and hübnerite in class 48 with wulfenite, at 48.01.01.02 and 48.01.01.01, under the wolframite series heading.
Documented failure: “tungstate” is not one class. Stolzite, Pb(WO4), and scheelite, Ca(WO4), are 07.GA.05 in Strunz, with wulfenite; ferberite and hübnerite, also (WO4) in their IMA formulas, are 04.DB.30. A rule that says “every tungstate or molybdate is a non-oxide” fails in Strunz for the wolframite pair, and a rule that says “anything with a metal-to-oxygen ratio of 1:2 is an oxide” fails for wulfenite. For wulfenite itself the two schemes agree. The wolframite pair is set out on ferberite vs wolframite.
Is wulfenite a mineral, and what is it made of?
A mineral: yes. Wulfenite has its own row on the September 2026 IMA list, Pb(MoO4), status G, grandfathered, 1845, Austria, with its first reference on page 504 of the Handbuch der Bestimmenden Mineralogie (Braumüller and Seidel, Wien, 1845). The general definition test is worked on is quartz a mineral. The Handbook sheet gives tetragonal, square flat tabular crystals to 11 cm, hardness 2.75 to 3, density 6.5 to 7.5 measured, streak white, and says it forms in the oxidized zone of hydrothermal lead deposits, the molybdenum commonly introduced externally. Large crystals at Tsumeb are on its Distribution field. The species page is wulfenite, and the tungsten partner, Pb(WO4), is stolzite.
Documented failure: the oxide columns. The sheet prints the Oudida, Morocco, analysis as MoO3 38.87 and PbO 60.91, total 99.78, corresponding to Pb1.01Mo1.00O4.00; its Chillago, Australia, analysis adds WO3 28.22 and corresponds to Pb1.00(Mo0.50W0.50)O4.00. Webmineral’s composition panel writes wulfenite as MoO3 39.21 and PbO2 65.15, totalling 104.36%. Two sources, two oxide sets, one formula: the oxide columns count the elements and do not classify the mineral.
Related questions. Whether it glows is on is wulfenite UV reactive, and its chemistry against uranium on is wulfenite radioactive. Wulfenite is 56.44% lead by mass; questions about lead minerals go to toxic minerals in a collection, and this page is not safety advice. More guides are in the collecting guides. We hold no catalogue and nothing here is offered for sale; the wanted list is the only commercial route.