Rigrahamite

Where it forms, where it's found

Type locality: Poudrette quarry (De-Mix quarry
Demix quarry
Uni-Mix quarry
Carrière Mont Saint-Hilaire
MSH)
Mont Saint-Hilaire
La Vallée-du-Richelieu RCM
Montérégie
Québec
Canada
45.5628°, -73.1417°

1recorded occurrences

Source · OpenStreetMap

Radioactivity

Crystallography

Crystal system: Monoclinic
Space group: P21/m
Cell parameters: a = 6.3846(1) Å · b = 30.8254(4) Å · c = 6.49473(8) Å
Cell angles: β = 95.354(1) °
Ratio a:b:c: 1 : 4.828 : 1.017

Chemical composition

Constituent elements: Mass composition breakdown
Element Atoms At. mass g/mol Mass g/mol Mass share
90ThThorium Thorium 2 232.038 464.076
40.48%
8OOxygen Oxygen 29 15.999 463.971
40.47%
20CaCalcium Calcium 2 40.078 80.156
6.99%
6CCarbon Carbon 6 12.011 72.066
6.29%
11NaSodium Sodium 2 22.990 45.980
4.01%
1HHydrogen Hydrogen 20 1.008 20.160
1.76%
Total 1146.409 100.00%
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
90ThThorium	Thorium	2	232.038	464.076	40.48%
8OOxygen	Oxygen	29	15.999	463.971	40.47%
20CaCalcium	Calcium	2	40.078	80.156	6.99%
6CCarbon	Carbon	6	12.011	72.066	6.29%
11NaSodium	Sodium	2	22.990	45.980	4.01%
1HHydrogen	Hydrogen	20	1.008	20.160	1.76%
	Total	1146.409	100.00%

Synonyms

Rigrahamiet

In other languages

German: IMA 2024-092a · Rigrahamit

Classification

Strunz

10th ed.

5.DB

5CarbonatesClass
5.DCarbonates with additional anions, with H₂ODivision
5.DBWith large and medium-sized cationsGroup
5.DBRigrahamiteSpecies

Literature, links & citation

Citations

2025Bosi, Ferdinando; Hatert, Frédéric; Pasero, Marco; Mills, Stuart J. (2025) IMA Commission on New Minerals, Nomenclature and Classification (CNMNC) – Newsletter 88. Mineralogical Magazine, 89. 1-11 doi:10.1180/mgm.2025.10183DOI: 10.1180/mgm.2025.10183

Cite this entry

@misc{mineral2026,
  author    = {Mineral Index editorial board},
  title     = {Rigrahamite — Mineral Index},
  year      = {2026},
  url       = {https://mineralindex.org/minerals/rigrahamite-498737},
  note      = {Accessed 2026-05-11}
}