Is azurite toxic?
Azurite, Cu3(CO3)2(OH)2, is 55.31% copper by mass, worked. What EH40 and COSHH say about copper, quoted, and the blue look-alike that adds lead. Not advice.
Azurite, Cu3(CO3)2(OH)2, a copper carbonate, is 55.31% copper by mass, worked from the IMA formula. UK workplace texts handle copper under COSHH, whose EH40 table lists “Copper and compounds: dust and mists (as Cu)” and names no mineral. A blue specimen that is really linarite also carries lead, under separate rules. Not advice.
In short
- What it is. The Handbook of Mineralogy azurite sheet gives Cu3(CO3)2(OH)2, monoclinic, hardness 3.5–4, brittle, density 3.773, azure-blue to pale blue with a pale blue streak, and says it “may constitute an ore of copper”. The September 2026 IMA-CNMNC Master List writes the same formula, G, 1824, France. Worked, copper is 190.64 of 344.67: 55.31%, as on is malachite toxic.
- Where copper sits in the rules. HSE EH40/2005 Workplace exposure limits Table 1 prints “Copper and compounds: dust and mists (as Cu)”, long-term 1 mg.m-3 and short-term 2 mg.m-3, and “Copper fume (as Cu)”, long-term 0.2 mg.m-3. COSHH 2002, regulation 2 defines a substance hazardous to health to include one for which HSE has approved a workplace exposure limit. These are workplace air limits expressed as copper, not thresholds for a specimen.
- The linarite check. A script read every cached Handbook sheet with copper in its formula and “azure” in its colour field: 5 sheets. Only linarite, PbCu(SO4)(OH)2, contains lead, 51.69% by mass, which takes it to the Control of Lead at Work Regulations as well. At density 5.35 a 20.00 g piece reads 16.26 g in water against azurite’s 14.70 g, 1.56 g heavier; the other three read 12.70–14.15 g.
- Documented failure: colour and streak. Azurite, linarite and cyanotrichite all print a pale blue streak, and azurite, linarite and connellite all print azure-blue. Neither separates the lead mineral. Nor does the check cover a mixed piece: the azurite sheet lists cerussite, a lead carbonate, among its associates, and a weighing reports the whole specimen.
- Not advice. This page is not health, safety or legal advice and gives no verdict on any specimen. Workplace duties are a matter for HSE, and exposure or symptoms for a clinician. The general site note is toxic minerals in a collection; the lead case is on is linarite toxic.
| Mineral and IMA formula | Cu, wt% | Pb, wt% | Density (sheet) | 20.00 g in water | Streak (sheet) | UK text by metal |
|---|---|---|---|---|---|---|
| Azurite, Cu3(CO3)2(OH)2 | 55.31 | 0 | 3.773 | 14.70 g | Pale blue | Copper: COSHH, EH40 Table 1 |
| Linarite, PbCu(SO4)(OH)2 | 15.85 | 51.69 | 5.35 | 16.26 g | Pale blue | Copper: COSHH, EH40; lead: CLAW 2002 |
| Connellite, Cu36(SO4)(OH)62Cl8·6H2O | 59.73 | 0 | 3.36–3.41 | 14.05–14.13 g | Pale greenish blue | Copper: COSHH, EH40 Table 1 |
| Buttgenbachite, Cu36(NO3)2Cl8(OH)62·nH2O | Not worked (n variable) | 0 | 3.36–3.42 | 14.05–14.15 g | Pale greenish blue | Copper: COSHH, EH40 Table 1 |
| Cyanotrichite, Cu4Al2(SO4)(OH)12(H2O)2 | 39.45 | 0 | 2.74–2.95 | 12.70–13.22 g | Pale blue | Copper: COSHH, EH40 Table 1 |
Is azurite toxic? What it is made of, worked
A copper carbonate, a little over half copper. The Handbook of Mineralogy azurite sheet gives Cu3(CO3)2(OH)2 and prints its ideal composition as CuO 69.23, H2O 5.23 and 25.54 for the carbon, under a label that reads CO3; worked, 25.54% is the CO2 equivalent. With Cu 63.546, C 12.011, O 15.999 and H 1.008, the formula mass is 344.67; copper is 55.31%, carbon 6.97%, oxygen 37.13% and hydrogen 0.58%. That copper figure agrees with is malachite toxic and is copper a mineral. From its cell, two formula units in 302.9 ų give 3.779, the sheet’s calculated 3.78.
The specimen the sheet analysed. Analysis (1) is from Chessy, France: CuO 69.08, CO3 25.46, H2O 5.46, total 100.00. Worked, that is 55.19% copper. The sheet records no hazard wording of any kind, and this page does not supply one. Its Occurrence field reads: “In the oxidized zones of copper deposits associated with carbonate rocks; may constitute an ore of copper.”
What do UK workplace rules say about copper?
Copper is listed; azurite is not. HSE EH40/2005 Workplace exposure limits (fourth edition, 2020), fetched 14 November 2026, prints two copper entries in Table 1: “Copper fume (as Cu)”, CAS 7440-50-8, a long-term exposure limit of 0.2 mg.m-3 over the 8-hour reference period and no short-term figure; and “Copper and compounds: dust and mists (as Cu)”, 1 mg.m-3 long-term and 2 mg.m-3 over the 15-minute reference period. A text search of EH40 finds no azurite, malachite or linarite; its list of synonyms has a single copper entry, Copper. Its paragraph 5 says substances that have been assigned a WEL are subject to the requirements of COSHH.
The COSHH link. COSHH 2002, regulation 2, read on legislation.gov.uk in its latest available revised form, defines a substance hazardous to health as a substance, including a mixture, which meets the CLP criteria for a health hazard class, or “for which the Health and Safety Executive has approved a workplace exposure limit”, among other limbs. Both copper entries are written “as Cu”, so they are expressed as copper, not as any mineral. This page does not convert them into amounts of azurite, and they are not a threshold for a specimen. How the same two rows sit beside lead for a lead-copper mineral is on is linarite toxic; the arsenic case is on is mimetite toxic.
Could a blue copper specimen contain lead? The linarite check
Method. A script read every Handbook sheet in this site’s cache with a PDF alongside it, 628 at its final run on 14 November 2026, and kept those whose header formula contains Cu and whose Color field contains “azure”, case-insensitive. Five remain: azurite (“Azure-blue, Berlin blue, very dark to pale blue”), buttgenbachite (“Deep azure-blue”), connellite (“Azure-blue”), cyanotrichite (“Sky-blue to azure-blue”) and linarite (“Bright to dark azure-blue”). The count is of what these cached sheets print, not of every blue copper mineral.
Result. Only linarite has lead in its formula: PbCu(SO4)(OH)2, 51.69% lead and 15.85% copper, the figures on is linarite toxic. Its sheet density is 5.35, so a clean 20.00 g piece reads 16.26 g in water, against 14.70 g for azurite at 3.773, 1.56 g apart. Connellite and buttgenbachite read 14.05 to 14.15 g and cyanotrichite 12.70 to 13.22 g. Linarite’s hardness is 2.5 against azurite’s 3.5–4. The weighing method is on how to measure specific gravity at home.
Documented failure: what the check cannot do. Streak does not separate the lead mineral: azurite, linarite and cyanotrichite all print pale blue. Colour does not either. A mixed piece defeats the weighing: the azurite sheet lists malachite, chrysocolla, brochantite, antlerite, cuprite, cerussite, smithsonite, calcite and dolomite as associates, and cerussite is a lead carbonate, so a specimen can carry lead with no linarite in it. The check is about composition. It says nothing about exposure, and neither a lower nor a higher reading makes a specimen safe or unsafe.
Is azurite rare, a mineral, or UV reactive?
A mineral, and not rare by its sheet. It has its own IMA row, G, 1824, France, and its Distribution field opens “Widespread, with many localities producing good crystals”: Chessy, France; Sardinia; the Altai, Russia; Touissit, Morocco; Chingola, Zambia; extraordinary examples from Tsumeb, Namibia; Bisbee, Morenci, Ajo and other Arizona mines; New Mexico and Utah; Mexico; Broken Hill and Girilambone, Australia; and Guangdong, China. The species page is azurite.
UV reactive? A ligature-aware search of the azurite sheet for fluorescence, phosphorescence and luminescence finds nothing, while the same search matches the hemimorphite and willemite sheets, which do print fluorescence. The sheet’s silence is not a measurement; the background is on fluorescent minerals explained. Radioactive? Its formula has no uranium, thorium or potassium; the general method is on is my mineral radioactive. A gemstone? No source fetched for this page covers it, so this page does not say.
Where should questions about azurite and health go?
Not to this page. It reports a formula, a sheet and the wording of UK texts. It gives no verdict on azurite or any specimen and no handling, cleaning, storage, cutting or display advice; nothing here says any amount, form or use of azurite is safe. EH40 itself says the absence of a substance from its list does not indicate that it is safe; a listed one is not given a verdict here either. Workplace duties belong with HSE; exposure or symptoms with a clinician. This is not health, safety or legal advice.
Where to go next. The species is on azurite; the other hazard pages are is malachite toxic, is linarite toxic, is mimetite toxic, is cerussite toxic and is pyromorphite toxic; the general note is toxic minerals in a collection, and more guides are in the collecting guides. Nothing on this site is offered for sale; the wanted list is the only commercial route.