Cervelleite

Where it forms, where it's found

Geological setting: Fracture fillings in highly altered silicified vitrophyre.
Type locality: Bambollita Mine
Moctezuma
Moctezuma Municipality
Sonora
Mexico
29.6925°, -109.7081°

63recorded occurrences

Source · OpenStreetMap

Physical

Hardness: 1Talc
2Gypsum
3Calcite
4Fluorite
5Apatite
6Orthoclase
7Quartz
8Topaz
9Corundum
10Diamond
Colour: dark grey · black
Cleavage: None Observed

Optical

Optical colour: Pale blue to pale green
Tropism: Isotropic
Reflectance R%: (39.8) 400, (40.1) 440, (39.7) 480, (38.9) 520, (37.8) 560, (36.8) 600, (35.8) 640, (34.9) 680, (34.4) 700

Reflected-light panel

R̄ 37.6 %isotropic · single curve

Specimen sRGB 215, 154, 88

White reference100 % reflector under same lamp

Wavelength550 nm · R 38.1 %

Reflected colour: Pale blue to pale green

Crystallography

Crystal system: Monoclinic
Cell parameters: a = 4.2696(4) Å · b = 6.9761(5) Å · c = 8.0423(7) Å
Cell angles: β = 100.332(6) °
Ratio a:b:c: 1 : 1.634 : 1.884
Unit cell volume: 235.66 Å³
Type-locality form: Thin rims around acanthite in hessite, blueish- to greenish white in fresh polished sections.
Comment: Space group P21/n. Originally considered to be cubic, with a = 14.03 A.

Chemical composition

Constituent elements: Mass composition breakdown
Element Atoms At. mass g/mol Mass g/mol Mass share
47AgSilver Silver 4 107.868 431.472
72.99%
52TeTellurium Tellurium 1 127.600 127.600
21.59%
16SSulfur Sulfur 1 32.060 32.060
5.42%
Total 591.132 100.00%
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
47AgSilver	Silver	4	107.868	431.472	72.99%
52TeTellurium	Tellurium	1	127.600	127.600	21.59%
16SSulfur	Sulfur	1	32.060	32.060	5.42%
	Total	591.132	100.00%

Synonyms

Cervelleiet
IMA1986-018
Mineral B (of Karup-Møller & Pauly)
UM1979-//-S:AgTe

In other languages

German: Cervelleit · IMA 1986-018
Italian: cervelleite · IMA1986-018
Chinese: 硫碲银矿

Classification

Strunz

10th ed.

2.BA.60

2Sulfides and SulfosaltsClass
2.BMetal Sulfides, M: S > 1: 1 (mainly 2: 1)Division
2.BAWith Cu, Ag, AuGroup
2.BA.60CervelleiteSpecies

CIM

—

3.2.8

3Sulphides, Selenides, Tellurides, Arsenides and Bismuthides (except the arsenides, antimonides and bismuthides of Cu, Ag and Au, which are included in Section 1)Class
3.2Sulphides etc. of AgGroup
3.2.8CervelleiteSpecies

Group, growth & confusion

2 members

Literature, links & citation

Citations

1989Criddle, Alan J., Chisholm, Jim E., Stanley, Chris J. (1989) Cervelleite, Ag4TeS, a new mineral from the Bambolla mine, Mexico, and a description of a photo-chemical reaction involving cervelleite, acanthite and hessite. European Journal of Mineralogy, 1 (3) 371-380 doi:10.1127/ejm/1/3/0371 DOI: 10.1127/ejm/1/3/0371
1990Jambor, John L., Burke, Ernst A. J. (1990) New Mineral Names. American Mineralogist, 75 (11-12) 1431-1437
1999Helmy, H.M. (1999) The Um Samiuki volcanogenic Zn-Cu-Pb-Ag deposit, Eastern Desert, Egypt: a possible new occurrence of cervelleite. The Canadian Mineralogist: 37: 143-154.
2005(2005) Cervelleite. Handbook of Mineralogy. Mineralogical Society of America
2006Novoselov, K. A., Belogub, E. V., Zaykov, V. V., Yakovleva, V. A. (2006) Silver sulfotellurides from volcanic-hosted massive sulfide deposits in the Southern Urals. Mineralogy and Petrology, 87 (3) 327-349 doi:10.1007/s00710-006-0132-xDOI: 10.1007/s00710-006-0132-x

Cite this entry

@misc{mineral2026,
  author    = {Mineral Index editorial board},
  title     = {Cervelleite — Mineral Index},
  year      = {2026},
  url       = {https://mineralindex.org/minerals/cervelleite-937},
  note      = {Accessed 2026-05-11}
}