Cannizzarite
Cannizzarite is a lead bismuth sulphide, Pb8Bi10S23 on the IMA list, from fumaroles on Vulcano: silvery laths to 2 mm, hardness about 2, density 6.7, bendable.
Cannizzarite is a lead bismuth sulphosalt, Pb8Bi10S23 to the IMA (grandfathered, 1924, Italy) and Pb46Bi54S127 to the Handbook. Its type locality is Vulcano, in the Lipari Islands, where it is fumarolic. It forms white to silvery grey laths to 2 mm that bend and twist: hardness about 2, density 6.7. On the Handbook formula it is 45.34% bismuth by mass.
In short
- Two formulas, nearly the same mineral. The Handbook of Mineralogy writes Pb46Bi54S127 and the IMA list Pb8Bi10S23. Worked on standard atomic weights, they give 38.30% and 36.96% lead, 45.34% and 46.60% bismuth, and 16.36% and 16.44% sulphur.
- The Handbook figure is reproduced exactly. Its ideal column for Pb46Bi54S127 prints Pb 38.30, Bi 45.34, S 16.36. The Vulcano analysis, recalculated here, reproduces the sheet's Pb44.70 Bi54.54 (S112.23 Se14.77). On that figure selenium fills 11.6% of the sulphur sites.
- No sheet in this site's reference set has bismuth in its formula. None of the 176 header formulas contains Bi (regex search by script); the word bismuth appears on five sheets: as native bismuth among the associates on four, and on stibnite, which forms a series with bismuthinite. Galena, stibnite and molybdenite, the grey metallic look-alikes in the set, are compared below. The cannizzarite sheet is not in the set.
- Somewhat malleable is an uncommon word on these sheets. Of the 176, three use malleable, and all three are native metals: copper, gold and silver. Stibnite and molybdenite are recorded as flexible but not elastic; cannizzarite is slightly elastic.
- The name honours Stanislao Cannizzaro, 1826 to 1910, the Italian chemist of the University of Rome.
| Species | Formula | Bi by mass | Pb by mass | Hardness | Density (measured) | Colour | Tenacity |
|---|---|---|---|---|---|---|---|
| Cannizzarite | Pb46Bi54S127 (Handbook); Pb8Bi10S23 (IMA) | 45.34%; 46.60% | 38.30%; 36.96% | About 2 | 6.7 | White to silvery grey, tarnishes iridescent | Somewhat malleable, slightly elastic, easily twisting and bending |
| Galena | PbS | 0% | 86.60% | 2.5 to 2.75 | 7.58 | Lead-grey | Brittle |
| Stibnite | Sb2S3 | 0% | 0% | 2 | 4.63 | Lead-grey, tarnishing blackish or iridescent | Highly flexible but not elastic; slightly sectile |
| Molybdenite | MoS2 | 0% | 0% | 1 to 1.5 | 4.62 to 4.73 | Lead-grey | Lamellae flexible, not elastic |
| Bismuthinite | Bi2S3 (IMA) | 81.29% | 0% | No sheet consulted | No sheet consulted | No sheet consulted | No sheet consulted |
| Galenobismutite | PbBi2S4 (IMA) | 55.48% | 27.50% | No sheet consulted | No sheet consulted | No sheet consulted | No sheet consulted |
What is cannizzarite?
Cannizzarite is a lead bismuth sulphide, a sulphosalt in which lead and bismuth share the sulphur. The September 2026 IMA-CNMNC Master List writes it Pb8Bi10S23 and records it as grandfathered, 1924, Italy. The Handbook header writes Pb46Bi54S127. The sheet's first reference is a 1925 Italian paper by Zambonini, de Fiore and Carobbi on a lead sulphobismuthide from Vulcano. The Distribution field marks Vulcano, in the Lipari Islands, as the type locality [TL].
It is monoclinic, space group P21/m. The sheet describes very thin single laths, to 2 mm, straight or commonly warped, with frayed ends, and felted masses and stellate groups. It is twinned as stellate trillings and simple V-shapes. It is opaque and metallic, white to silvery grey, tarnishing iridescent, with strong anisotropism from blue to grey. The hardness is about 2 (VHN 132 at a 20 g load), and the density is 6.7 measured and 6.95 calculated.
Type material is at the University of Florence, number 14398/G, the Natural History Museum, number 128.28, and the National School of Mines, Paris. At 2 mm, it is a micromount species; see what is a micromount.
Pb46Bi54S127 or Pb8Bi10S23? A worked composition
Both formulas balance. In Pb46Bi54S127, 46 lead at +2 and 54 bismuth at +3 make +254, and 127 sulphur at −2 make −254. In Pb8Bi10S23, 16 + 30 = +46 against −46. They differ in the lead-to-bismuth ratio: 0.852 in the Handbook formula and 0.800 in the IMA's.
On standard atomic weights (lead 207.2, bismuth 208.98, sulphur 32.06):
- Pb46Bi54S127, formula mass 24887.74: Pb 38.30%, Bi 45.34%, S 16.36%. The Handbook's column (3), its ideal for this formula, prints exactly these figures.
- Pb8Bi10S23, formula mass 4484.78: Pb 36.96%, Bi 46.60%, S 16.44%.
The analyses sit between and around the two. Vulcano, an average of eight microprobe analyses, reads Pb 36.21%, Bi 44.56%, S 14.07% and Se 4.56%. Converted to atoms on 127 sulphur plus selenium, that is Pb44.69 Bi54.53 S112.23 Se14.77, matching the sheet's own recalculation to within 0.01. On that figure selenium fills 11.6% of the anion sites. The Mittal-Hohtenn tunnel analysis from Switzerland reads Pb 37.51%, Bi 44.96% and S 16.25%, with small silver and tellurium. So the lead figure alone cannot choose between the two formulas. That is a question for the literature the IMA list cites (Canadian Mineralogist 48, 2010), not for a hand specimen.
How to tell cannizzarite from stibnite, galena and molybdenite
Weight first. Cannizzarite measures 6.7. Stibnite is 4.63 and molybdenite 4.62 to 4.73, so cannizzarite is about 45% denser than stibnite. Galena, at 7.58, is 13% denser again, but it is brittle and breaks into cubes; cannizzarite bends. At 2 mm a density test is not practical. The numbers matter more when a felted mass is large enough to weigh. See how to measure specific gravity at home.
Then tenacity, read carefully. Stibnite is highly flexible but not elastic, and molybdenite's lamellae are flexible, not elastic. Cannizzarite is somewhat malleable, slightly elastic, easily twisting and bending. Method: all 176 sheets searched case-insensitively for malleable and elastic. Three use malleable: copper, gold and silver, all native metals. Elastic appears on 13 sheets, but on six of them it is negated (not elastic or inelastic); the other seven are micas, cronstedtite, brucite and hematite.
Then colour and association. Cannizzarite is white to silvery grey and tarnishes iridescent; galena, stibnite and molybdenite are all lead-grey on their sheets. At Vulcano, cannizzarite grows with lillianite, mozgovaite, kirkiite, barberiite, galenobismutite, bismuthinite, galena, gold and tellurium. For a silvery lath from a bismuth-bearing assemblage, an analysis decides between the lead bismuth sulphides. The grey-metal comparisons are also on galena and stibnite.
Where cannizzarite is found
The sheet records cannizzarite associated with deep fumarolic activity at Vulcano, Italy. It also occurs in sulphide veinlets in a greisen tin-tungsten deposit in granite, the Shumilovsk deposit in Russia, where it grows with wolframite, cassiterite, bismuthinite, galena, cosalite, heyrovskýite, galenobismutite, bursaite, tetradymite, joséite-B, bismuth and quartz.
The full distribution: Vulcano, in the Lipari Islands [TL], and the Ginevro mine, Elba, Italy; Santa Maria, Val Medel, Graubünden, Goppenstein, Lotschental, and the Mittal-Hohtenn tunnel, Valais, Switzerland; the Felbertal tungsten mine, Salzburg, Austria; the Shumilovsk Sn–W deposit, west Transbaikal, and the Vysokogorsk deposit, Far Eastern Region, Russia; the Hobenzan granitic complex, Yamaguchi, Japan; and Landsman Camp, Graham Co., Arizona. No British locality is recorded.
Against the 176 sheets in the set, Vulcano appears once, on the hydrobasaluminite sheet (Alum Cave, Vulcano). The rest of the sulphosalts are indexed at the species index. We hold no catalogue and nothing here is offered for sale; the wanted list is the only commercial route.