Serandite is a mineral with formula Na(Mn2+,Ca)2Si3O8(OH). The mineral was discovered in Guinea in 1931 and named for J. M. Sérand. Serandite is generally red, brown, black or colorless. The correct name lacks an accent.
| Serandite | |
|---|---|
 Serandite from Mont Saint-Hilaire, Quebec, Canada | |
| General | |
| Category | Inosilicates |
| Formula (repeating unit) | Na(Mn2+,Ca)2Si3O8(OH) |
| IMA symbol | Srd |
| Strunz classification | 9.DG.05 |
| Dana classification | 65.2.1.5 |
| Crystal system | Triclinic |
| Crystal class | Pinacoidal (1) (same H-M symbol) |
| Space group | P1 |
| Unit cell | a = 7.683(1) Å, b = 6.889(1) Å c = 6.747(1) Å, α = 90.53(5)° β = 94.12(2)°, γ = 102.75(2)° Z = 2 |
| Identification | |
| Colour | salmon pink to orange |
| Twinning | Around [010] composition plane {100}, less commonly contact twin on {110} |
| Cleavage | Perfect on {001} and {100} |
| Fracture | Irregular, uneven |
| Tenacity | Brittle |
| Mohs scale hardness | 5 to 5.5 |
| Luster | Vitreous to greasy; fibrous aggregates are dull to silky |
| Streak | White |
| Diaphaneity | Transparent, Translucent |
| Density | 3.34 g/cm3 (measured) |
| Optical properties | Biaxial (+) |
| Refractive index | nα = 1.668 nβ = 1.671 nγ = 1.703 |
| Birefringence | δ = 0.035 |
| 2V angle | 39° |
| Dispersion | r < v moderate |
| References | |
Description
Serandite is transparent to translucent and is normally salmon-pink, light pink, rose-red, orange, brown, black, or colorless; in thin section, it is colorless. Octahedrally bonded Mn(II) is the primary contributor to the mineral's pink colors.
Crystals of the mineral can be prismatic to acicular and elongated along [010], bladed, blocky, or tabular and flattened on {100}, occur as a radiating aggregate, or have massive habit. Sérandite is a member of the wollastonite group and is the manganese analogue of pectolite. It is sometimes used as a gemstone.
History
Serandite was discovered on Rouma Island, part of the Los Islands in Guinea. The mineral was described by À. Lacroix in the journal Comptes rendus hebdomadaires des séances de l'Académie des Sciences. He named it sérandite in honor of J.M. Sérand, a mineral collector who helped in the collection of the mineral.
Occurrence and distribution
Serandite has been found in Australia, Brazil, Canada, Guinea, Italy, Japan, Namibia, Norway, Russia, South Africa, and the United States. The type material is held at the National Museum of Natural History in Washington, D.C.
At Mont Saint-Hilaire, Quebec, serandite occurs in sodalite xenoliths and pegmatites cutting syenites within an intrusive alkalic gabbro-syenite complex. In Point of Rocks, New Mexico, it occurs in vugs in phonolite. At the Tumannoe deposit in Russia, serandite occurs in a manganese rich deposit associated with volcanic rocks and terrigenous (non-marine) sediments which has been altered by contact metamorphism.
Serandite has been found in association with aegirine, analcime, arfvedsonite, astrophyllite, eudialyte, fluorite, leucophanite, mangan-neptunite, microcline, nepheline, sodalite, and villiaumite.
References
- 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.
- "Sérandite" (PDF). Handbook of Mineralogy. Mineral Data Publishing. Archived from the original (PDF) on September 11, 2021. Retrieved July 11, 2012.
- "Sérandite". Mindat. Retrieved July 11, 2012.
- "Serandite". Webmineral. Retrieved July 25, 2012.
- Hålenius, U., Hatert, F., Pasero, M., and Mills, S.J., IMA Commission on New Minerals, Nomenclature and Classification (CNMNC) Newsletter 28. Mineralogical Magazine 79(7), 1859–1864
- Manning, p. 357.
- Gemstones of North America – Volume 3 – Page 417 John Sinkankas – 1959
- Lacroix, p. 189.
Bibliography
- Lacroix, À. (January 26, 1931). "Les pegmatites de la syénite sodalitique de l'île Rouma (archipel de Los, Guinée française). Description d'un nouveau minéral (sérandite) qu'elles renferment" (PDF). Comptes rendus hebdomadaires des séances de l'Académie des Sciences (in French). 192: 189–194.
- Manning, P. G. (June 1968). "Absorption spectra of the manganese-bearing chain silicates pyroxmangite, rhodonite, bustamite and serandite" (PDF). The Canadian Mineralogist. 9 (3). Mineralogical Association of Canada: 348–357.
Further reading
- Jacobsen, Steven D.; Smyth, Joseph R.; Swope, R. Jeffrey; Sheldon, Robert I. (May–June 2000). "Two proton positions in the very strong hydrogen bond of serandite, NaMn2[Si3O8(OH)]" (PDF). American Mineralogist. 85 (5 & 6): 745–752. Bibcode:2000AmMin..85..745J. doi:10.2138/am-2000-5-613. S2CID 14785226.
- Takeuchi, Yoshio; Yasuhiro, Kudoh; Yamanaka, Takamitsu (April 1976). "Crystal chemistry of the serandite-pectolite series and related minerals" (PDF). American Mineralogist. 61 (3 & 4): 229–237.
External links
Media related to Serandite at Wikimedia Commons
Serandite is a mineral with formula Na Mn2 Ca 2Si3O8 OH The mineral was discovered in Guinea in 1931 and named for J M Serand Serandite is generally red brown black or colorless The correct name lacks an accent SeranditeSerandite from Mont Saint Hilaire Quebec CanadaGeneralCategoryInosilicatesFormula repeating unit Na Mn2 Ca 2Si3O8 OH IMA symbolSrdStrunz classification9 DG 05Dana classification65 2 1 5Crystal systemTriclinicCrystal classPinacoidal 1 same H M symbol Space groupP1Unit cella 7 683 1 A b 6 889 1 A c 6 747 1 A a 90 53 5 b 94 12 2 g 102 75 2 Z 2IdentificationColoursalmon pink to orangeTwinningAround 010 composition plane 100 less commonly contact twin on 110 CleavagePerfect on 001 and 100 FractureIrregular unevenTenacityBrittleMohs scale hardness5 to 5 5LusterVitreous to greasy fibrous aggregates are dull to silkyStreakWhiteDiaphaneityTransparent TranslucentDensity3 34 g cm3 measured Optical propertiesBiaxial Refractive indexna 1 668 nb 1 671 ng 1 703Birefringenced 0 0352V angle39 Dispersionr lt v moderateReferencesDescriptionSerandite is transparent to translucent and is normally salmon pink light pink rose red orange brown black or colorless in thin section it is colorless Octahedrally bonded Mn II is the primary contributor to the mineral s pink colors Crystals of the mineral can be prismatic to acicular and elongated along 010 bladed blocky or tabular and flattened on 100 occur as a radiating aggregate or have massive habit Serandite is a member of the wollastonite group and is the manganese analogue of pectolite It is sometimes used as a gemstone HistorySerandite was discovered on Rouma Island part of the Los Islands in Guinea The mineral was described by A Lacroix in the journal Comptes rendus hebdomadaires des seances de l Academie des Sciences He named it serandite in honor of J M Serand a mineral collector who helped in the collection of the mineral Occurrence and distributionSerandite has been found in Australia Brazil Canada Guinea Italy Japan Namibia Norway Russia South Africa and the United States The type material is held at the National Museum of Natural History in Washington D C At Mont Saint Hilaire Quebec serandite occurs in sodalite xenoliths and pegmatites cutting syenites within an intrusive alkalic gabbro syenite complex In Point of Rocks New Mexico it occurs in vugs in phonolite At the Tumannoe deposit in Russia serandite occurs in a manganese rich deposit associated with volcanic rocks and terrigenous non marine sediments which has been altered by contact metamorphism Serandite has been found in association with aegirine analcime arfvedsonite astrophyllite eudialyte fluorite leucophanite mangan neptunite microcline nepheline sodalite and villiaumite ReferencesWarr 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 Serandite PDF Handbook of Mineralogy Mineral Data Publishing Archived from the original PDF on September 11 2021 Retrieved July 11 2012 Serandite Mindat Retrieved July 11 2012 Serandite Webmineral Retrieved July 25 2012 Halenius U Hatert F Pasero M and Mills S J IMA Commission on New Minerals Nomenclature and Classification CNMNC Newsletter 28 Mineralogical Magazine 79 7 1859 1864 Manning p 357 Gemstones of North America Volume 3 Page 417 John Sinkankas 1959 Lacroix p 189 Bibliography Lacroix A January 26 1931 Les pegmatites de la syenite sodalitique de l ile Rouma archipel de Los Guinee francaise Description d un nouveau mineral serandite qu elles renferment PDF Comptes rendus hebdomadaires des seances de l Academie des Sciences in French 192 189 194 Manning P G June 1968 Absorption spectra of the manganese bearing chain silicates pyroxmangite rhodonite bustamite and serandite PDF The Canadian Mineralogist 9 3 Mineralogical Association of Canada 348 357 Further readingJacobsen Steven D Smyth Joseph R Swope R Jeffrey Sheldon Robert I May June 2000 Two proton positions in the very strong hydrogen bond of serandite NaMn2 Si3O8 OH PDF American Mineralogist 85 5 amp 6 745 752 Bibcode 2000AmMin 85 745J doi 10 2138 am 2000 5 613 S2CID 14785226 Takeuchi Yoshio Yasuhiro Kudoh Yamanaka Takamitsu April 1976 Crystal chemistry of the serandite pectolite series and related minerals PDF American Mineralogist 61 3 amp 4 229 237 External linksMedia related to Serandite at Wikimedia Commons
