Is wulfenite UV reactive?
Not on the record. Wulfenite’s Handbook sheet prints no fluorescence and the International Gem Society says none, but 6 of the 9 associates it names may glow.
Not on the record. The Handbook of Mineralogy sheet for wulfenite, PbMoO4, hardness 2.75 to 3, prints no fluorescence, and the International Gem Society gives its luminescence as none. But 6 of the 9 minerals the sheet names as associates may fluoresce, cerussite yellow among them, so a glow on a wulfenite specimen is a reason to look at its matrix.
In short
- The sheet’s words. The Handbook of Mineralogy wulfenite sheet has no fluorescence line. A script that tolerates a dropped or garbled fl ligature finds nothing there, while the same script finds the lines on the hemimorphite and willemite sheets, its positive controls. The International Gem Society wulfenite data panel agrees: Luminescence, None; Luminescence Present, No.
- The neighbour check. The sheet names 9 associates. Read the same way, 6 of their sheets record fluorescence: cerussite yellow under LW, anglesite yellow, smithsonite pale green or pale blue, hemimorphite bluish under SW, pyromorphite yellow to orange, mimetite reddish yellow. Vanadinite, descloizite and plattnerite record none. Every one of the six says may.
- Documented failure: absence is not a test result. A missing line on a sheet means the sheet records nothing, not that every specimen has been tried. The two sources found agree on none, and a search of the text of Modreski 1987, New Mexico Geology 9 finds no mention of wulfenite. A dark wulfenite under a lamp is consistent with the record; a glowing spot is first a question about what it is.
- Where a glow on the piece comes from. Modreski’s Blanchard mine photograph shows a late coating of fine-grained, powdery, white cerussite fluorescing yellow under longwave UV, activator unknown. Cerussite is first on wulfenite’s association line. A lamp can tell a collector which part of a specimen to look at, not that the wulfenite glows.
- Lamps and safety. Lamp choice is on best UV lamp for mineral collecting and the principles on fluorescent minerals explained. Exposure limits for 180 to 400 nm are in the ICNIRP 2004 guidelines on limits of exposure to ultraviolet radiation; this page is not safety advice. Lead is covered on toxic minerals in a collection.
| Sheet | Luminescence line as printed | Band named | Qualifier | Hardness | Density (meas.) | 20.00 g in water |
|---|---|---|---|---|---|---|
| Wulfenite | None printed (IGS: Luminescence None) | — | — | 2.75 to 3 | 6.5 to 7.5 | 16.92 to 17.33 g |
| Cerussite | May fluoresce yellow under LW UV | LW | May | 3 to 3.5 | 6.55 | 16.95 g |
| Anglesite | May fluoresce yellow under UV | None named | May | 2.5 to 3 | 6.38 | 16.87 g |
| Smithsonite | May fluoresce pale green or pale blue under UV | None named | May | 4 to 4.5 | 4.43 | 15.49 g |
| Hemimorphite (positive control) | May fluoresce bluish under SW UV | SW | May | 4.5 to 5 | 3.475 | 14.24 g |
| Pyromorphite | May fluoresce yellow to orange under LW and SW UV | LW and SW | May | 3.5 to 4 | 7.04 | 17.16 g |
| Mimetite | May fluoresce reddish yellow under LW or SW UV | LW or SW | May | 3.5 to 4 | 7.24 | 17.24 g |
| Vanadinite | None printed | — | — | 2.5 to 3 | 6.88 | 17.09 g |
| Descloizite | None printed | — | — | 3 to 3.5 | About 6.2 | 16.77 g |
| Plattnerite | None printed | — | — | 5.5 | 9.564 | 17.91 g |
Does wulfenite glow under a UV lamp?
Not according to the two references that say anything. The Handbook of Mineralogy wulfenite sheet describes PbMoO4 as tetragonal, hardness 2.75 to 3, measured density 6.5 to 7.5, with a white streak and a resinous to adamantine lustre, and it prints no fluorescence, phosphorescence or luminescence. Its physical line notes only that individuals may be piezoelectric. The International Gem Society panel gives Luminescence: None, and hardness 2.5 to 3 and specific gravity 6.5 to 7.0, which differ slightly from the sheet; this page uses the sheet’s figures.
How the absence was checked. pdftotext can drop or garble the fl ligature, so the script matched uoresc with any stray glyph before it, as well as phosphoresc, luminesc, UV and ultraviolet. It found hemimorphite’s line, printed as may °uoresce bluish under SW UV, and willemite’s, so the method sees a mangled word. On the wulfenite sheet it found nothing, and a raw search for the fragments uor, lumin, phosph and UV also returned nothing.
Why might a wulfenite specimen glow anyway?
Because of what grows with it. The wulfenite sheet’s association line names cerussite, anglesite, smithsonite, hemimorphite, vanadinite, pyromorphite, mimetite, descloizite, plattnerite and Fe–Mn oxides. Six of those nine mineral sheets record fluorescence: cerussite yellow under LW UV, anglesite yellow under UV, smithsonite pale green or pale blue under UV, hemimorphite bluish under SW UV, pyromorphite yellow to orange under LW and SW, and mimetite reddish yellow under LW or SW. vanadinite, descloizite and plattnerite record none.
A photographed case. Modreski 1987, New Mexico Geology 9 shows fluorite from the Blanchard mine, Hansonburg district, New Mexico, with a late coating of fine-grained, powdery, white cerussite that fluoresces yellow under longwave UV, the activator in the cerussite unknown. That is a cerussite on fluorite, not on wulfenite. It shows the kind of thin associate coating that can glow on a specimen whose main mineral records nothing.
Which reading tells the glow from the wulfenite?
Position and shape, then the associate’s own page. A glow that follows a white crust, a granular patch or the matrix rather than the square wulfenite tablet points to an associate. The associate pages carry their own UV assets, not repeated here: the either-lamp rule on is mimetite UV reactive, the band readings on is smithsonite UV reactive and is hemimorphite UV reactive, and the Mo ladder for the scheelite family on is scheelite fluorescent.
Where the balance helps and fails. Worked as 20 − 20/D on the sheets’ measured densities, a clean 20.00 g piece reads 16.92 to 17.33 g in water as wulfenite. Cerussite (16.95 g), vanadinite (17.09 g), pyromorphite (17.16 g) and mimetite (17.24 g) all fall inside that band, so weight does not separate wulfenite from the lead associates; hemimorphite (14.24 g) and smithsonite (15.49 g) sit well below it. The method is on how to measure specific gravity at home.
Should you test wulfenite under shortwave or longwave?
The sheet gives no band to test for. Because the record is none, there is no wulfenite band to prefer. The associates differ: cerussite’s sheet names LW, hemimorphite’s SW, pyromorphite’s both, and anglesite and smithsonite no band. Which lamp to own is on best UV lamp for mineral collecting; how fluorescence works is on fluorescent minerals explained.
Not advice. Shortwave and longwave lamps emit ultraviolet; the exposure limits for 180 to 400 nm are set out in the ICNIRP 2004 guidelines on limits of exposure to ultraviolet radiation, and this page does not interpret them. Wulfenite is 56.44% lead by mass, worked from PbMoO4; lead is covered on toxic minerals in a collection and is galena toxic. This page is not safety or health advice.
Light sensitivity is a different question from UV response and is discussed on the wulfenite species page. The rest of the guides are under the collecting guides. We hold no catalogue and nothing here is offered for sale; the wanted list is the only commercial route.