Cassagnaite

Where it forms, where it's found

Geological setting: Hydrothermal alteration of braunite-bearing layered mineralization and metacherts.
Type locality: Cassagna Mine
Ne
Genoa
Liguria
Italy
44.3358°, 9.4753°

3recorded occurrences

Source · OpenStreetMap

Physical

Transparency: Transparent
Colour: Golden brown
Streak: Nearly white
Tenacity: brittle
Cleavage: On (001)
Density: 3.22 g/cm³

Optical

Pleochroism: Weak
Very weak. N (i.e. parallel to a) = golden yellow-brown and n = pale golden yellow-brown.
Extinction: Parallel extinction
UV response: Not fluorescent
Notes: Positive elongation and low interference colours. Refractive index values are N (i.e. parallel to a) = 1.810 (± 0.005) and n: 1.800 (± 0.005).

Crystallography

Crystal system: Orthorhombic
Space group: #50
Cell parameters: a = 6.066(1) Å · b = 8.908(1) Å · c = 18.995(2) Å
Ratio a:b:c: 1 : 1.469 : 3.131
Z: 2
Morphology: Prism (011) and the pinacoids (001) and (100).
Type-locality form: Fracture fillings in braunite + quartz layered mineralizations. Very rare isolated prismatic to tabular crystals < 0.06 mm. A few crystal aggregates to 1 mm.

Crystal structure

Chemical composition

Constituent elements: Mass composition breakdown
Element Atoms At. mass g/mol Mass g/mol Mass share
8OOxygen Oxygen 26 15.999 415.974
39.69%
26FeIron Iron 4 55.845 223.380
21.31%
20CaCalcium Calcium 4 40.078 160.312
15.30%
14SiSilicon Silicon 5 28.085 140.425
13.40%
23VVanadium Vanadium 2 50.942 101.884
9.72%
1HHydrogen Hydrogen 6 1.008 6.048
0.58%
Total 1048.023 100.00%
Mass share = atoms × atomic mass ÷ molar mass × 100
From IMA formula

Mass composition breakdown
Element	Atoms	At. mass g/mol	Mass g/mol	Mass share
8OOxygen	Oxygen	26	15.999	415.974	39.69%
26FeIron	Iron	4	55.845	223.380	21.31%
20CaCalcium	Calcium	4	40.078	160.312	15.30%
14SiSilicon	Silicon	5	28.085	140.425	13.40%
23VVanadium	Vanadium	2	50.942	101.884	9.72%
1HHydrogen	Hydrogen	6	1.008	6.048	0.58%
	Total	1048.023	100.00%

Synonyms

Cassagnaiet
IMA2006-019a

In other languages

German: Cassagnait · IMA 2006-019a
Italian: cassagnaite

Classification

Strunz

10th ed.

9.BJ.65

9SilicatesClass
9.BSorosilicatesDivision
9.BJSorosilicates with Si₃O₁₀, Si₄O₁₁, etc. anions; cations in octahedral [6] and greater coordinationGroup
9.BJ.65CassagnaiteSpecies

Literature, links & citation

Citations

2008Basso, Riccardo, Carbone, Cristina, Palenzona, Andrea (2008) Cassagnaite, a new, V-bearing silicate mineral from the Cassagna mine, northern Apennines, Italy. European Journal of Mineralogy, 20 (1) 95-100 doi:10.1127/0935-1221/2007/0019-1777 DOI: 10.1127/0935-1221/2007/0019-1777
2008Piilonen, P. C., Poirier, G., Tait, K. T. (2008) New Mineral Names. American Mineralogist, 93 (10) 1686-1691 doi:10.2138/am.2008.527DOI: 10.2138/am.2008.527
2009Palenzona, A., Martinelli, A. (2009) Cassagnaite una nuova specie vanadinifera dalla Val Graveglia, Genova. Rivista Mineralogica Italiana: 4: 268-270.
2013(2013) Cassagnaite. Handbook of Mineralogy. Mineralogical Society of America

Cite this entry

@misc{mineral2026,
  author    = {Mineral Index editorial board},
  title     = {Cassagnaite — Mineral Index},
  year      = {2026},
  url       = {https://mineralindex.org/minerals/cassagnaite-31591},
  note      = {Accessed 2026-05-11}
}