| Marrite | |
|---|---|
 The two arrows point to the marrite microcrystals (one or two at each arrow, dull), the rest is galena (bright) | |
| General | |
| Category | Sulfosalt mineral |
| Formula (repeating unit) | PbAgAsS3 |
| IMA symbol | Mrr[1] |
| Strunz classification | 2.JB.15 |
| Crystal system | Monoclinic |
| Crystal class | Prismatic (2/m) (same H-M symbol) |
| Space group | P21/a |
| Unit cell | a = 7.29 Å, b = 12.68 Å, c = 5.99 Å; β = 91.22°; V = 553.57 Å3; Z = 4 |
| Identification | |
| Formula mass | 486.19 g/mol |
| Color | Lead gray, steel gray |
| Crystal habit | Tabular or striated crystals |
| Twinning | Partly bent twin lamellae observable in polished section. |
| Cleavage | None |
| Fracture | Conchoidal |
| Tenacity | Brittle |
| Mohs scale hardness | 3 |
| Luster | Metallic |
| Streak | Black with brownish tint |
| Diaphaneity | Opaque |
| Specific gravity | 5.82 |
| Optical properties | Biaxial |
| Refractive index | Anistrophic |
| Pleochroism | White, with red internal reflections. |
| Other characteristics | Of hydrothermal origin along with other sulfosalts in dolomite. |
| References | [2][3][4][5] |
Marrite (mar'-ite) is a mineral with the chemical formula PbAgAsS3. It is the arsenic equivalent of freieslebenite (PbAgSbS3), but also displays close polyhedral characteristics with sicherite and diaphorite.[6] Marrite was first described in 1905,[7] and was named in honor of geologist John Edward Marr (1857–1933) of Cambridge, England.[5]
- ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
- ^ Mineralienatlas
- ^ Cite error: The named reference
Mindatwas invoked but never defined (see the help page). - ^ Cite error: The named reference
HBMwas invoked but never defined (see the help page). - ^ a b "Marrite Mineral Data." http://webmineral.com/data/Marrite.shtml. Retrieved 8 September 2010.
- ^ Berlepsch, P., Makovicky E., and Armbruster, T. (2002) Structural relationships between sicherite, marrite, freieslebenite, and diaphorite: Analysis based on anionic nets and polyhedral characteristics(178th edition) 75-91 p. E. Schweizerbart'sche Verlagsbuchhandlung. Stuttgart, Germany.
- ^ Solly, RH (1905). "Some new minerals from the Binnenthal, Switzerland" (PDF). Mineralogical Magazine. 14: 72–82. doi:10.1180/minmag.1905.014.64.03.