Serandite

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title: "Serandite" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["triclinic-minerals", "sodium-minerals", "manganese(ii)-minerals", "calcium-minerals", "hydroxide-minerals", "inosilicates", "gemstones", "minerals-in-space-group-2"] description: "Mineral" topic_path: "general/triclinic-minerals" source: "https://en.wikipedia.org/wiki/Serandite" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Mineral ::

::data[format=table title="infobox mineral"]

Field	Value
name	Serandite
category	Inosilicates
boxbgcolor	#FA8072
image	Serandite-Aegirine-20264.jpg
imagesize	260px
caption	Serandite from Mont Saint-Hilaire, Quebec, Canada
formula	Na(Mn2+,Ca)2Si3O8(OH)
IMAsymbol	Srd
strunz	9.DG.05
dana	65.2.1.5
system	Triclinic
class	Pinacoidal ()
(same H-M symbol)
symmetry	P
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
twinning	Around [010] composition plane {100}, less commonly contact twin on {110}
cleavage	Perfect on {001} and {100}
fracture	Irregular, uneven
tenacity	Brittle
mohs	5 to 5.5
luster	Vitreous to greasy; fibrous aggregates are dull to silky
refractive	nα = 1.668
nβ = 1.671
nγ = 1.703
opticalprop	Biaxial (+)
birefringence	δ = 0.035
2V	39°
dispersion	r
streak	White
density	3.34 g/cm3 (measured)
diaphaneity	Transparent, Translucent
references
colour	salmon pink to orange
::

| name = Serandite | category = Inosilicates | boxwidth = | boxbgcolor =#FA8072 | image = Serandite-Aegirine-20264.jpg | imagesize = 260px | caption = Serandite from Mont Saint-Hilaire, Quebec, Canada | formula = Na(Mn2+,Ca)2Si3O8(OH) | IMAsymbol = Srd | molweight = | strunz = 9.DG.05 | dana = 65.2.1.5 | system = Triclinic | class = Pinacoidal () (same H-M symbol) | symmetry = P | 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 | color = | habit = | twinning = Around [010] composition plane {100}, less commonly contact twin on {110} | cleavage = Perfect on {001} and {100} | fracture = Irregular, uneven | tenacity = Brittle | mohs = 5 to 5.5 | luster = Vitreous to greasy; fibrous aggregates are dull to silky | polish = | refractive = nα = 1.668 nβ = 1.671 nγ = 1.703 | opticalprop = Biaxial (+) | birefringence = δ = 0.035 | 2V = 39° | dispersion = r | pleochroism = | fluorescence= | absorption = | streak = White | gravity = | density = 3.34 g/cm3 (measured) | melt = | fusibility = | diagnostic = | solubility = | diaphaneity = Transparent, Translucent | other = | references = |colour=salmon pink to orange}} 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.

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.

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.

History

Serandite was discovered on Rouma Island, part of the Los Islands in Guinea. 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

Bibliography

References

1. Warr, L.N.. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine.
2. "Sérandite". Mineral Data Publishing.
3. "Sérandite". Mindat.
4. "Serandite". Webmineral.
5. 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
6. Octahedrally bonded [[manganese
7. The mineral was described by À. Lacroix in the journal ''[[Comptes rendus hebdomadaires des séances de l'Académie des Sciences]]''.Lacroix, p. 189.

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