Serandite is a mineral with formula Na(Mn²⁺,Ca)₂Si₃O₈(OH). The mineral was discovered in

Guinea Guinea ( ),, fuf, 𞤘𞤭𞤲𞤫, italic=no, Gine, wo, Gine, nqo, ߖߌ߬ߣߍ߫, bm, Gine officially the Republic of Guinea (french: République de Guinée), is a coastal country in West Africa. It borders the Atlantic Ocean to the we ...

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. Octahedrally bonded Mn(II) is the primary contributor to the mineral's pink colors.Manning, p. 357. Crystals of the mineral can be prismatic to acicular and elongated along 10 bladed, blocky, or tabular and flattened on , 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.Gemstones of North America - Volume 3 - Page 417 John Sinkankas - 1959

History

Serandite was discovered on Rouma Island, part of the

Los Islands LOS, or Los, or LoS may refer to: Science and technology * Length of stay, the duration of a single episode of hospitalisation * Level of service, a measure used by traffic engineers * Level of significance In statistical hypothesis testing, ...

in Guinea. The mineral was described by À. Lacroix in the journal '' Comptes rendus hebdomadaires des séances de l'Académie des Sciences''.Lacroix, p. 189. 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 In biology, a type is a particular specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally attached. In other words, a type is an example that serves to anchor or centralizes the ...

is held at the National Museum of Natural History in Washington, D.C. At Mont Saint-Hilaire, Quebec, serandite occurs in sodalite xenoliths and

pegmatite A pegmatite is an igneous rock showing a very coarse texture, with large interlocking crystals usually greater in size than and sometimes greater than . Most pegmatites are composed of quartz, feldspar, and mica, having a similar silicic com ...

s cutting

syenite Syenite is a coarse-grained intrusive igneous rock with a general composition similar to that of granite, but deficient in quartz, which, if present at all, occurs in relatively small concentrations (< 5%). Some syenites contain larger proport ...

s within an intrusive

alkalic Alkalinity (from ar, القلوي, al-qaly, lit=ashes of the saltwort) is the capacity of water to resist acidification. It should not be confused with basicity, which is an absolute measurement on the pH scale. Alkalinity is the strength of ...

gabbro-

complex. In Point of Rocks, New Mexico, it occurs in vugs in

phonolite Phonolite is an uncommon extrusive rock, of intermediate chemical composition between felsic and mafic, with texture ranging from aphanitic (fine-grained) to porphyritic (mixed fine- and coarse-grained). Phonolite is a variation of the igneous ...

. At the Tumannoe deposit in Russia, serandite occurs in a manganese rich deposit associated with volcanic rocks and

terrigenous In oceanography, terrigenous sediments are those derived from the erosion of rocks on land; that is, they are derived from ''terrestrial'' (as opposed to marine) environments. Consisting of sand, mud, and silt carried to sea by rivers, their ...

(non-marine) sediments which has been altered by contact metamorphism. Serandite has been found in association with aegirine, analcime, arfvedsonite, astrophyllite, eudialyte, fluorite,

leucophanite Leucophanite is an inosilicate mineral with the chemical formula . It may contain cerium substituting in the calcium position. It occurs in pegmatites and alkali igneous complexes as yellow, greenish or white triclinic crystals and has been fou ...

, mangan-neptunite, microcline,

nepheline Nepheline, also called nephelite (), is a rock-forming mineral in the feldspathoid groupa silica-undersaturated aluminosilicate, Na3 K Al4 Si4 O16, that occurs in intrusive and volcanic rocks with low silica, and in their associated pegmatites ...

sodalite Sodalite ( ) is a tectosilicate mineral with the formula , with royal blue varieties widely used as an wikt:ornamental, ornamental gemstone. Although massive sodalite samples are opaque, crystals are usually transparent to translucent. Sodalite i ...

, and

villiaumite Villiaumite is a rare halide mineral composed of sodium fluoride, Na F. It is very soluble in water and some specimens fluoresce under long and short wave ultraviolet light. It has a Mohs hardness of 2.5 and is usually red, pink, or orange in col ...

References

Bibliography

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External links