Alvesite

Where it forms, where it's found

Type locality: Ruins of Lombadas syenite xenolith occurrence
Ribeira Grande
São Miguel
Azores
Portugal
37.7739°, -25.4586°

1recorded occurrences

Source · OpenStreetMap

Crystallography

Crystal system: Orthorhombic
Cell parameters: a = 14.0876(4) Å · b = 14.5333(8) Å · c = 14.4183(6) Å
Ratio a:b:c: 1 : 1.032 : 1.023
Comment: the space group is Cmce (a very rare case among minerals)

Chemical composition

Constituent elements: Mass composition breakdown
Element Atoms At. mass g/mol Mass g/mol Mass share
8OOxygen Oxygen 17 15.999 271.983
45.49%
14SiSilicon Silicon 6 28.085 168.510
28.19%
40ZrZirconium Zirconium 1 91.224 91.224
15.26%
19KPotassium Potassium 1 39.098 39.098
6.54%
11NaSodium Sodium 1 22.990 22.990
3.85%
1HHydrogen Hydrogen 4 1.008 4.032
0.67%
Total 597.837 100.00%
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	17	15.999	271.983	45.49%
14SiSilicon	Silicon	6	28.085	168.510	28.19%
40ZrZirconium	Zirconium	1	91.224	91.224	15.26%
19KPotassium	Potassium	1	39.098	39.098	6.54%
11NaSodium	Sodium	1	22.990	22.990	3.85%
1HHydrogen	Hydrogen	4	1.008	4.032	0.67%
	Total	597.837	100.00%

Synonyms

Alvesiet
Alvesitt
IMA2023-069

In other languages

German: Alvesit

Classification

Strunz

10th ed.

9.DG

9SilicatesClass
9.DInosilicatesDivision
9.DGInosilicates with 3-periodic single and multiple chainsGroup
9.DGAlvesiteSpecies

Literature, links & citation

Citations

2023Bosi, Ferdinando, Hatert, Frédéric, Pasero, Marco, Mills, Stuart J. (2023) Newsletter 76. Mineralogical Magazine, 1-5 doi:10.1180/mgm.2023.89 DOI: 10.1180/mgm.2023.89

Cite this entry

@misc{mineral2026,
  author    = {Mineral Index editorial board},
  title     = {Alvesite — Mineral Index},
  year      = {2026},
  url       = {https://mineralindex.org/minerals/alvesite-470940},
  note      = {Accessed 2026-05-11}
}