Belmonteite

Where it forms, where it's found

Type locality: Gambatesa Mine
Reppia
Ne
Genoa
Liguria
Italy
44.3597°, 9.4500°

1recorded occurrences

Source · OpenStreetMap

Safety & handling

Crystallography

Crystal system: Orthorhombic
Cell parameters: a = 8.8418(9) Å · b = 23.031(2) Å · c = 13.527(1) Å
Ratio a:b:c: 1 : 2.605 : 1.530
Comment: Space group Cmce

Chemical composition

Constituent elements: Mass composition breakdown
Element Atoms At. mass g/mol Mass g/mol Mass share
8OOxygen Oxygen 15 15.999 239.985
43.33%
33AsArsenic Arsenic 2 74.922 149.844
27.05%
25MnManganese Manganese 2 54.938 109.876
19.84%
20CaCalcium Calcium 1 40.078 40.078
7.23%
1HHydrogen Hydrogen 14 1.008 14.112
2.55%
Total 553.895 100.00%
Mass share = atoms × atomic mass ÷ molar mass × 100
From Mindat formula

Mass composition breakdown
Element	Atoms	At. mass g/mol	Mass g/mol	Mass share
8OOxygen	Oxygen	15	15.999	239.985	43.33%
33AsArsenic	Arsenic	2	74.922	149.844	27.05%
25MnManganese	Manganese	2	54.938	109.876	19.84%
20CaCalcium	Calcium	1	40.078	40.078	7.23%
1HHydrogen	Hydrogen	14	1.008	14.112	2.55%
	Total	553.895	100.00%

Synonyms

Belmonteiet

In other languages

German: Belmonteit · IMA 2024-040

Classification

Strunz

10th ed.

8.CE

8Phosphates, Arsenates, VanadatesClass
8.CPhosphates without additional anions, with H₂ODivision
8.CEWith only medium-sized cations, RO₄:H₂O about 1:2.5Group
8.CEBelmonteiteSpecies

Literature, links & citation

Citations

—Biagioni, C., Sejkora, J., and Dolníček, Z.: Belmonteite, IMA 2024-040, in: CNMNC Newsletter 81, Eur. J. Mineral., 36, https://doi.org/10.5194/ejm-36-917-2024, 2024.

Cite this entry

@misc{mineral2026,
  author    = {Mineral Index editorial board},
  title     = {Belmonteite — Mineral Index},
  year      = {2026},
  url       = {https://mineralindex.org/minerals/belmonteite-471415},
  note      = {Accessed 2026-05-11}
}