Is torbernite radioactive?
Yes. Torbernite, a secondary copper uranyl phosphate, is radioactive on its Handbook sheet, and by mass it is 47.15% uranium to 6.29% copper. Not safety advice.
Yes. The Handbook of Mineralogy sheet for torbernite, hardness 2 to 2.5, ends its physical properties with one word: Radioactive. Its IMA formula, Cu(UO2)2(PO4)2(H2O)4·8H2O, works out at 47.15% uranium and 6.29% copper by mass: 7.5 times as much uranium as copper. It is a uranium mineral with some copper, not the reverse. This is not safety advice.
In short
- The sheet says so in one word. The Handbook of Mineralogy torbernite sheet (revised 30 January 2021) reads H2O content varies with relative humidity. Radioactive. It places the species in the autunite group, as an uncommon secondary mineral of the oxidised zone of some uraniferous copper deposits.
- The 7.5-to-1 rule. Worked on standard atomic weights, Cu(UO2)2(PO4)2(H2O)4·8H2O is 47.15% uranium and 6.29% copper. Uranium outweighs copper 7.5 to 1. A green copper-bearing plate on a label reading torbernite is, by mass, a uranium mineral.
- A real analysis agrees. The Handbook’s analysis from Leupoldsdorf, Bavaria, gives UO3 57.03% and CuO 7.73%: 47.46% uranium and 6.18% copper. The ideal column on the same sheet, UO3 56.65%, is 47.14% uranium. The analysed material came out slightly above the ideal figure, not below it.
- Drying changes the name, not the answer. The torbernite sheet says it becomes dull on dehydration to metatorbernite, and the metatorbernite sheet also ends Radioactive. What leaves is water; the uranium stays.
- Facts only; the rest belongs elsewhere. This page gives no dose figures and no storage or handling instructions of its own. The Ionising Radiations Regulations 2017 are enforced by the HSE; personal questions go to UKHSA, the HSE or a Radiation Protection Adviser. This is not health, safety or legal advice.
| Rank | Species | Formula (IMA) | Uranium by mass | Copper by mass | Uranium to copper | IMA status, year or number | Handbook sheet |
|---|---|---|---|---|---|---|---|
| 1 | Roubaultite | Cu2O2(UO2)3(CO3)2(OH)2(H2O)4 | 59.74% | 10.63% | 5.6 to 1 | A, 1970-030 | Not read |
| 2 | Vandenbrandeite | Cu(UO2)(OH)4 | 59.27% | 15.82% | 3.7 to 1 | G, 1932 | Not read |
| 3 | Marthozite | Cu(UO2)3(SeO3)2O2(H2O)4·4H2O | 54.77% | 4.87% | 11.2 to 1 | A, 1968-016 | Not read |
| 4 | Pseudojohannite | Cu3(OH)2[(UO2)4O4(SO4)2](H2O)10·2H2O | 53.58% | 10.73% | 5.0 to 1 | A, 2000-019 | Not read |
| 5 | Cuprosklodowskite | Cu(UO2)2(SiO3OH)2(H2O)4·2H2O | 53.02% | 7.08% | 7.5 to 1 | G, 1933 | “Radioactive.” |
| 6 | Metatorbernite | Cu(UO2)2(PO4)2(H2O)4·4H2O | 50.77% | 6.78% | 7.5 to 1 | G, 1916 | “Radioactive.” |
| 7 | Johannite | Cu(UO2)2(SO4)2(OH)2(H2O)4·4H2O | 48.88% | 6.53% | 7.5 to 1 | G, 1830 | Not read |
| 8 | Torbernite | Cu(UO2)2(PO4)2(H2O)4·8H2O | 47.15% | 6.29% | 7.5 to 1 | A, 1980 s.p. | “Radioactive.” |
| 9 | Metazeunerite | Cu(UO2)2(AsO4)2(H2O)4·4H2O | 46.42% | 6.20% | 7.5 to 1 | G, 1937 | “Radioactive.” |
| 10 | Sengierite | Cu2(UO2)2(VO4)2(OH)2(H2O)6 | 45.81% | 12.23% | 3.7 to 1 | Rn, 2007 s.p. | Not read |
| 11 | Zeunerite | Cu(UO2)2(AsO4)2(H2O)4·8H2O | 43.37% | 5.79% | 7.5 to 1 | G, 1872 | “Radioactive” |
| 12 | Ulrichite | CaCu(UO2)(PO4)2(H2O)4 | 37.45% | 10.00% | 3.7 to 1 | A, 1988-006 | Not read |
| 13 | Paddlewheelite | MgCa5Cu2(UO2)4(CO3)12(H2O)33 | 34.67% | 4.63% | 7.5 to 1 | A, 2017-098 | Not read |
| 14 | Voglite | Ca2Cu(UO2)(CO3)4·6H2O | 31.24% | 8.34% | 3.7 to 1 | G, 1853 | Not read |
| 15 | Derriksite | Cu4(UO2)(SeO3)2(OH)6 | 27.04% | 28.88% | 0.9 to 1 | A, 1971-033 | Not read |
| 16 | Kristekite | Cu2(H2O)4(UO2)(SeO3)3·4H2O | 25.81% | 13.78% | 1.9 to 1 | A, 2025-101 | Not read |
| 17 | Deloryite | Cu4(UO2)Mo2O8(OH)6 | 25.16% | 26.87% | 0.9 to 1 | A, 1990-037 | Not read |
| 18 | Astrocyanite-(Ce) | Cu2Ce2(UO2)(CO3)5(OH)2·1.5H2O | 22.92% | 12.24% | 1.9 to 1 | A, 1989-032 | Not read |
| 19 | Demesmaekerite | Pb2Cu5(UO2)2(SeO3)6(OH)6(H2O)2 | 21.92% | 14.63% | 1.5 to 1 | A, 1965-019 | Not read |
Is torbernite radioactive? What the Handbook sheet says
Torbernite is radioactive because uranium is part of its formula, not an impurity in it. The Handbook of Mineralogy torbernite sheet prints the word Radioactive at the end of its physical properties, after Hardness = 2-2.5 D(meas.) = 3.22 and the note that its water content varies with relative humidity. The sheet’s header formula is Cu(UO2)2(PO4)2·12H2O; the IMA-CNMNC list of minerals (September 2026) writes Cu(UO2)2(PO4)2(H2O)4·8H2O, A, 1980 s.p., Czech Republic. They are the same atoms, written two ways.
Worked uranium. Formula mass 1009.72, from U 238.029, Cu 63.546, P 30.974, O 15.999 and H 1.008. Two uranium atoms make 476.06 of it: 47.15%. A 10 g piece of ideal torbernite holds 4.7 g of uranium; real specimens carry matrix, so that is a figure for the mineral, not for the rock it sits on. The torbernite species page covers habit, localities and identification.
Checked against a real analysis. The sheet’s analysis (1) is from Leupoldsdorf, Bavaria: UO3 57.03%, P2O5 14.50%, SiO2 0.59%, CuO 7.73%, H2O 20.30%. Uranium is 83.22% of UO3 by mass, so that analysis is 47.46% uranium, slightly above the 47.15% ideal. Uranium is 47 to 48% of the mineral on both counts.
Why a green copper mineral counts as a uranium mineral: the 7.5-to-1 rule
Torbernite contains 7.5 times as much uranium as copper by mass. The same formula gives copper 6.29%, and the Leupoldsdorf analysis 6.18%. The rule a collector can carry: if the label names a copper uranyl species, read it as a uranium mineral first. Nearly half of torbernite’s mass is uranium; about a sixteenth is copper.
The survey. Method: a script parses every row of the September 2026 IMA list and keeps formulas containing both the element symbols Cu and U; a second, independent scan of every line of the list for tokens containing both finds the same 19 rows. They are tabled above, ranked by uranium worked from each IMA formula. Torbernite ranks 8th of 19. 17 of the 19 carry more uranium than copper by mass; the two that do not are derriksite (27.04% against 28.88%) and deloryite (25.16% against 26.87%).
What the survey does not show. Five of the 19 sheets were read for this page: torbernite, metatorbernite, zeunerite, metazeunerite and cuprosklodowskite. All five print Radioactive. The other fourteen were not read, so the table says not read rather than inferring a statement. Uranium content is arithmetic, not a measurement of activity, and no dose follows from it.
Does torbernite stop being radioactive when it dries out?
No: drying turns it into metatorbernite, and the metatorbernite sheet also says radioactive. The torbernite sheet’s lustre line ends becoming dull on dehydration to metatorbernite. The Handbook metatorbernite sheet describes that species as typically pseudomorphous after torbernite by stepped dehydration, says it can also form directly above 75 °C, and ends its physical properties Radioactive. Water leaves; the uranium does not.
The arsenate pair behaves the same way. The Handbook zeunerite sheet, for the copper uranyl arsenate, reads Radioactive; commonly dehydrates to metazeunerite, and the metazeunerite sheet also ends Radioactive. So the boundary of the answer is not the hydration state. A torbernite label on a plate that has since dried is a metatorbernite question, not a radioactivity question.
Not repeated here. The mass and volume arithmetic of that dehydration is worked on the metatorbernite page, and the calcium analogue on is autunite dangerous. Neither is restated. How to tell which uranium micas a collection holds is on is my mineral radioactive.
Who answers the safety questions about torbernite
Not this page. We give no dose figures and no storage or handling instructions of our own, and nothing here is health, safety or legal advice. The site’s existing guidance is on how to store radioactive mineral specimens and toxic minerals in a collection; read those, and take anything personal to a professional.
The regulation, quoted rather than interpreted. Regulation 3(1) of the Ionising Radiations Regulations 2017 (SI 2017/1075) says they apply to any practice and to certain work in radon atmospheres. The HSE’s legal-base page says any employer who undertakes work with ionising radiation must comply with IRR17, and that the regulations also apply to work with natural radiation. Whether any of that touches a private collection is a question for the HSE or UKHSA, not for a mineral website.
Where to go. For radiation protection in the UK, the UK Health Security Agency and the HSE; at work, a Radiation Protection Adviser, as the site’s radioactivity guide explains. More guides are in the collecting guides. Nothing here is offered for sale; the wanted list is the only commercial route.