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Sérandite
Current inventory:  0 gems
 

Chemistry:  Na(Mn²⁺,Ca)₂Si₃O₈(OH)  [Sodium Manganese Calcium Silicate Hydroxide]

Discovered in 1931;   IMA status: Valid (pre-IMA; Grandfathered).
Sérandite is named after J.M. Sérand, mineral collector of west Africa, who assisted collecting the mineral.

Classification

Mineral Classification:

Silicates

Strunz 8th Ed. ID:

8/F.18-80

Nickel-Strunz 10th Ed. ID:

9.DG.05

9 : SILICATES (Germanates)
D : Inosilicates
G : Inosilicates with 3-periodic single and multiple chains

Related to:

Wollastonite Group. Pectolite - Schizolite - Sérandite Series. The managanese analogue of Pectolite.

Crystal Data

Crystallography:

Triclinic - Pinacoidal

Crystal Habit:

Prismatic to acicular crystals, elongated along [010]; bladed, blocky, or tabular crystals, flattened on [100], to 20 cm. As radiating crystal aggregates; massive.

Twinning:

Around [010], with composition plane [100]; less commonly contact twinned by reflection on [110].

Physical Properties

Cleavage:

[100] Perfect, [001] Perfect

Fracture:

Irregular/Uneven to Splintery

Tenacity:

Brittle

Hardness (Mohs):

5.0 - 5.5

Density:

3.34 (g/cm³)

Luminescence:

None

Radioactivity:

Not Radioactive

Optical Properties

Color:

Pale Pink, Salmon-Red, Salmon-Orange, deep Orange, Rose-Red, Brown, Colorless

Transparency:

Translucent to Transparent

Luster:

Vitreous, Greasy; fibrous aggregates are Dull to Silky

Refractive Index:

1.668 - 1.703  Biaxial ( + )

Birefringence:

0.0250 - 0.0360

Dispersion:

Moderate; r < v

Pleochroism:

None

Occurances

Geological Setting:

In sodalite xenoliths and pegmatites cutting syenites and nepheline syenites in an intrusive alkalic gabbro-syenite complex (Mont Saint-Hilaire, Canada); in vugs in phonolite (Point of Rocks, New Mexico, USA); in a contact metamorphosed terrigenous volcanogenic manganese deposit (Tumannoe deposit, Russia).

Common Associations:

Aegirine, Analcime, Arfvedsonite, Astrophyllite, Eudialyte, Fluorite, Leucophanite, Nepheline, Sodalite, Villiaumite (Rouma Isle, Guinea); Aegirine, Analcime, Mangan-Neptunite, Microcline (Mont Saint-Hilaire, Canada).

Common Impurities:

Al, Fe, Mg, K, H₂O

Type Locality:

Rouma Island (Roume; Roma; Ruma), Los Archipelago (Los Islands), Guinea

Year Discovered:

1931

View mineral photos:

Sérandite Mineral Photos and Locations

More Information

Mindat.org
Webmineral.com

Sérandite is an extremely rare gem that is one of the best known rare minerals from Mont Saint-Hilaire, Quebec, Canada. It contains manganese which gives it the beautiful salmon pink color similar to other manganese containing minerals such as Rhodochrosite and Rhodonite. Sérandite is often associated with other rare minerals such as Aegirine, Analcime, Arfvedsonite, Astrophyllite, Eudialyte, Nepheline, Sodalite and Villiaumite. Sérandite crystals are rarely transparent in large enough sizes for faceting, so faceted gems are usually translucent and included.

The main source of gemmy, translucent Sérandite crystals is the Poudrette quarry, Mont Saint-Hilaire, Rouville County, Québec, Canada.
 

  
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