Carraraite

Where it forms, where it's found

Geological setting: Marble altered by aluminium rich hydrothermal solutions acting on sulfides.
Type locality: Gioia quarries (Gioia-Casette quarries
Gioia-Casette quarrying basin)
Casette
Massa
Massa-Carrara Province
Tuscany
Italy
44.0762°, 10.1559°

3recorded occurrences

Source · OpenStreetMap

Physical

Lustre: Vitreous
Transparency: Transparent
Colour: White
Streak: White
Cleavage: None Observed

Optical

Optical type: Uniaxial (+)
Refractive index: 1.479 – 1.509
Surface relief: Low
Principal indices: n_ω 1.479 · n_ε 1.509

Michel-Lévy diagramhighlighted lineδ = 0.0300

Attainable Michel-Lévy rangeΔ ∈ [0, t·δ_max]300 nm1st order

Δ = 0Δ_max

Section thickness10 μmStage rotation0°

Thin-section mosaic70 grains · random 3D orientations

PPL

pleochroism per grain

XPL

independent extinctions · rotate the stage

Interference simulatorsingle grain · PPL ↔ XPL

PPL

pleochroism only · colour blends on rotation

XPL

interference colour · extinct every 90°

Retardation300 nm

Order1st order

XPL colour

Crystallography

Crystal system: Hexagonal
Cell parameters: a = 11.056 Å · b = 3 Å · c = 10.629(6) Å
Ratio a:b:c: 1 : 0.271 : 0.961
Morphology: Hexagonal crystals, prismatic (100), tabular (001).
Comment: Space group P63 or P63/m

Crystal structure

Chemical composition

Constituent elements: Mass composition breakdown
Element Atoms At. mass g/mol Mass g/mol Mass share
8OOxygen Oxygen 25 15.999 399.975
59.95%
20CaCalcium Calcium 3 40.078 120.234
18.02%
32GeGermanium Germanium 1 72.630 72.630
10.89%
16SSulfur Sulfur 1 32.060 32.060
4.81%
1HHydrogen Hydrogen 30 1.008 30.240
4.53%
6CCarbon Carbon 1 12.011 12.011
1.80%
Total 667.150 100.00%
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	25	15.999	399.975	59.95%
20CaCalcium	Calcium	3	40.078	120.234	18.02%
32GeGermanium	Germanium	1	72.630	72.630	10.89%
16SSulfur	Sulfur	1	32.060	32.060	4.81%
1HHydrogen	Hydrogen	30	1.008	30.240	4.53%
6CCarbon	Carbon	1	12.011	12.011	1.80%
	Total	667.150	100.00%

Synonyms

Carraraiet
IMA1998-002

In other languages

French: Carraraïte
German: Carrarait · IMA 1998-002
Italian: Carraraite

Classification

Strunz

10th ed.

7.DG.15

7SulfatesClass
7.DSulfates (selenates, etc.) with additional anions, with H₂ODivision
7.DGWith large and medium-sized cations; with NO₃, CO₃, B(OH)₄, SiO₄ or IO₃Group
7.DG.15CarraraiteSpecies

Dana

8th ed.

32.04.04.06

32Compound SulfatesClass
32.04Hydrated Compound Sulfates containing Hydroxyl or HalogenType
32.04.04Charlesite GroupGroup
32.04.04.06CarraraiteSpecies

Group, growth & confusion

14 members

Literature, links & citation

Citations

2001Merlino, Stefano, Orlandi, Paolo (2001) Carraraite and zaccagnaite, two new minerals from the Carrara marble quarries: their chemical compositions, physical properties, and structural features. American Mineralogist, 86 (10) 1293-1301 doi:10.2138/am-2001-1017 DOI: 10.2138/am-2001-1017
2005(2005) Carraraite. Handbook of Mineralogy. Mineralogical Society of America

Cite this entry

@misc{mineral2026,
  author    = {Mineral Index editorial board},
  title     = {Carraraite — Mineral Index},
  year      = {2026},
  url       = {https://mineralindex.org/minerals/carraraite-7038},
  note      = {Accessed 2026-05-11}
}