Linarite
Linarite is PbCu(SO4)(OH)2: azure-blue, pale blue streak, hardness 2.5, density 5.35. Named for Linares, Spain; fine crystals from Red Gill, Caldbeck Fells.
Linarite is a lead copper sulphate, PbCu(SO4)(OH)2, named for Linares in Spain: monoclinic, bright to dark azure-blue with a pale blue streak, hardness 2.5, measured density 5.35, with a perfect cleavage and crystals to 8 cm. It is 51.69% lead and 15.85% copper by mass. British collectors know it from Caldbeck Fells and Leadhills.
In short
- Spanish by name, British by reputation. The September 2026 IMA-CNMNC Master List gives PbCu(SO4)(OH)2, status G, 1822, with Spain as country of first description. The Handbook of Mineralogy sheet prints the same formula and names it for its occurrence at Linares, Jaén Province. It is not named for Lanarkshire; that is lanarkite.
- The pale-blue streak key. Of seven blue copper minerals tabled below, 5 print a pale blue streak on their Handbook sheets: linarite, azurite, chenite, diaboleite and cyanotrichite. A pale blue streak says “blue copper mineral”; it does not say which. Hardness and crystal shape narrow it to linarite.
- Documented failure: diaboleite. Deep blue, pale blue streak, hardness 2.5, density 5.42: a 20.00 g piece reads 16.31 g in water against linarite’s 16.26 g, 0.05 g apart. Neither streak, hardness nor weight separates them. Shape does: diaboleite is tetragonal, in square tablets; linarite is monoclinic, elongated.
- The analysis checks out one to one to one. Worked from the sheet’s Arenas, Sardinia analysis, the molar ratio of PbO, CuO and SO3 is 1.01 : 0.99 : 1, against 1 : 1 : 1 in the formula. The ideal column, 55.69% PbO and 19.85% CuO, is reproduced from standard atomic weights.
- Where. The sheet gives fine crystals from Red Gill and other mines in Caldbeck Fells, and names Leadhills; also large crystals from the Mammoth-St. Anthony mine, Arizona, Kisamori, Japan, and Tsumeb. Lead minerals are covered on toxic minerals in a collection; this page gives no health or handling advice, and none of it is advice.
| Species | IMA formula | Lead in formula | System (Handbook) | Colour (Handbook) | Streak (Handbook) | Hardness | Density (measured) | Cleavage (Handbook) |
|---|---|---|---|---|---|---|---|---|
| Linarite | PbCu(SO4)(OH)2 | Yes, 51.69% | Monoclinic | Bright to dark azure-blue | Pale blue | 2.5 | 5.35 | Perfect, one direction; one interrupted |
| Diaboleite | CuPb2Cl2(OH)4 | Yes, 67.18% | Tetragonal | Deep blue | Pale blue | 2.5 | 5.42 | Perfect, basal |
| Chenite | CuPb4(SO4)2(OH)6 | Yes, 69.85% | Triclinic | Sky-blue | Pale blue | About 2.5 | 5.98 | Good, one direction; traces of a second |
| Azurite | Cu3(CO3)2(OH)2 | No | Monoclinic | Azure-blue, Berlin blue, very dark to pale blue | Pale blue | 3.5 to 4 | 3.773 | Perfect but interrupted; fair; poor |
| Cyanotrichite | Cu4Al2(SO4)(OH)12(H2O)2 | No | Orthorhombic | Sky-blue to azure-blue | Pale blue | Not determined | 2.74 to 2.95 | Not printed |
| Connellite | Cu36(SO4)(OH)62Cl8·6H2O | No | Hexagonal | Azure-blue | Pale greenish blue | 3 | 3.36 to 3.41 | Not printed |
| Boleite | KAg9Pb26Cu24Cl62(OH)48 | Yes | Cubic | Deep Prussian blue to indigo | Blue, with greenish tint | 3 to 3.5 | 5.054 | Perfect, cubic |
What is linarite? A lead copper sulphate named for Linares
The names. The September 2026 IMA-CNMNC Master List lists linarite as PbCu(SO4)(OH)2, status G, year 1822, country Spain. The Handbook sheet prints the same formula and gives the name as for its occurrence at Linares, Spain; type material is at the Mining Academy, Freiberg. Linarite and lanarkite are both found at Leadhills and their names differ by two letters, but they come from different places and different chemistry: lanarkite is a white lead mineral with no copper. Why so many names end the same way is on why mineral names end in -ite.
What it looks like. Monoclinic crystals elongated along one axis, typically tabular, with about another 40 forms known, to 8 cm; also crusts and aggregates. Twinning is common. The cleavage is perfect on {100} and interrupted in a second direction; the fracture conchoidal and the mineral brittle. Colour bright to dark azure-blue, deep blue in transmitted light; streak pale blue; lustre vitreous to subadamantine. Under a microscope it is pleochroic from pale blue to Prussian blue.
Composition, worked on standard atomic weights (Pb 207.2, Cu 63.546, S 32.06, O 15.999, H 1.008): formula mass 400.82, of which 51.69% is lead and 15.85% copper. As oxides, 55.69% PbO, 19.85% CuO, 19.97% SO3 and 4.49% H2O, the sheet’s ideal column. The sheet’s one analysis, from Arenas, Sardinia, recalculated to 100%, gives molar PbO : CuO : SO3 of 1.01 : 0.99 : 1. The copper-share comparison with caledonite is on the caledonite page and is not repeated here.
Is it linarite or azurite? The pale-blue streak key
Streak first, and it is not enough. A script read the Streak field on each of the seven sheets in the table. Five print pale blue: linarite, azurite, chenite, diaboleite and cyanotrichite. Connellite prints pale greenish blue and boleite blue with a greenish tint. So a pale blue line on a streak plate places the piece among the blue copper minerals and stops there.
The key. Among the five pale-blue-streak sheets, the three that print a hardness of about 2.5 all carry lead in the formula: linarite, chenite and diaboleite. Azurite, the copper-only blue on the same streak, is 3.5 to 4, a full Mohs step and more harder. Then shape: linarite monoclinic and elongated, chenite triclinic, diaboleite tetragonal in square tablets. The method, and why a hardness test belongs on an inconspicuous spot, is on how to test mineral hardness properly.
Documented failure: boleite. It carries lead, yet its sheet gives hardness 3 to 3.5, so “soft means lead” is a description of the five pale-blue sheets, not a law. Boleite is separated by its cubic crystals and greenish-tinted streak; it has its own page, boleite. Cyanotrichite has no hardness on its sheet, and its sheet describes acicular crystals, unlike linarite’s. The weight test between lead-copper and copper-only blues is the caledonite page’s 16 g line; this page does not repeat it.
Linarite or diaboleite? When weight, streak and hardness all agree
Three matches. Diaboleite, CuPb2Cl2(OH)4 on the IMA list, is deep blue with a pale blue streak and hardness 2.5, exactly as linarite. Its density, 5.42, against linarite’s 5.35, gives 16.31 g and 16.26 g in water for a 20.00 g piece: a 0.05 g gap that a kitchen balance will not resolve. The method is on how to measure specific gravity at home.
What separates them is on the sheets’ crystal fields. Diaboleite: tetragonal, crystals tabular, with a square or octagonal outline, perfect basal cleavage, adamantine and pearly on cleavages. Linarite: monoclinic, crystals elongated along one axis, vitreous to subadamantine. Diaboleite carries chlorine and no sulphate; linarite is a sulphate.
Locality helps too. The diaboleite sheet’s British localities are Higher Pitts Farm and the Merehead quarry in the Mendip Hills, and Padstow Consols in Cornwall; it does not name Leadhills or Caldbeck Fells. The linarite sheet names both. A label is evidence, not proof, but a deep blue square tablet labelled Mendip deserves a second look before it is called linarite.
Where linarite is found: Red Gill, Leadhills and Arizona
The Distribution field says linarite occurs in small amounts at many localities, of which only a few are given. In Britain: fine crystals from the Red Gill and other mines, Caldbeck Fells, Cumbria; and Leadhills, Lanarkshire, covered on Leadhills and Wanlockhead. The sheet’s powder pattern is from Red Gill mine material. Its association list is brochantite, anglesite, caledonite, leadhillite, cerussite, malachite and hemimorphite.
Elsewhere, per the sheet: Linares, Jaén Province, Spain; Arenas and San Giovanni, Sardinia; large crystals in the Kisamori mine, Akita Prefecture, Japan; Broken Hill, New South Wales; large crystals at the Mammoth-St. Anthony mine, Tiger, and the Grand Reef mine, Arizona; the Blanchard and Mex-Tex mines, New Mexico; the Tintic district, Utah; Cerro Gordo and the Blue Bell claims, California; and large crystals from Tsumeb, Namibia. It is an uncommon secondary mineral of the oxidised zone of lead-copper deposits.
Lead minerals are covered on toxic minerals in a collection; this page gives no health or handling advice, and none of it is advice. The rest of the reference section is at the species index. We hold no catalogue and nothing here is offered for sale; the wanted list is the only commercial route.