ClassicGems.net

Marialite

Discovered in 1866; IMA status: Valid (pre-IMA; Grandfathered)

Chemistry

Chemical Formula:

Na₄Al₃Si₉O₂₄Cl

Sodium Aluminum Silicate Cloride

Molecular Weight:

845.11 gm

Composition:

Sodium

10.88 %

Na

14.67 %

Na₂O

Aluminum

9.58 %

Al

18.10 %

Al₂O₃

Silicon

29.91 %

Si

63.99 %

SiO₂

Chlorine

4.20 %

Cl

4.20 %

Cl

-

Cl

-0.95 %

-O=Cl₂

Oxygen

45.44 %

O

100.00 %

100.00 %

= TOTAL OXIDE

Classification

Mineral Classification:

Silicates (Germanates)

Strunz 8th Ed. ID:

8/J.13-10

Nickel-Strunz 10th Ed. ID:

9.FB.15

9 : SILICATES (Germanates)
F : Tektosilicates without zeolitic H₂O
B : Tektosilicates with additional anions 

Related to:

Scapolite Gourp. Marialite-Meionite Sseries.

Members of Group:

Scapolite Gourp: Kembleite, Marialite, Meionite, Scapolite, Silvialie

Varieties:

Algerite

Synonyms:

Marialite (of von Roth), Marialith, Mizzonite

Crystal Data

Crystallography:

Tetragonal - Dipyramidal

Crystal Habit:

TCrystals prismatic, typically with flat pyramidal terminations, striated || [001], to 1.5 m; granular, massive.

Twinning:

None

Physical Properties

Cleavage:

Distinct on {100} and {110}

Fracture:

Irregular/uneven, conchoidal

Tenacity:

Very brittle

Moh's Hardness:

5.5 - 6.0

Density:

2.50 - 2.62 (g/cm³)

Luminescence:

Commonly fluoresces orange to bright yellow or red under SW and/or LW UV light.

Radioactivity:

Not Radioactive

Optical Properties

Color:

Colorless, white, grey; pink, violet, blue, yellow, brown, orange-brown; colorless in thin section.

Transparency:

Transparent to opaque

Luster:

Vitreous, pearly, resinous

Refractive Index:

1.532 - 1.550  Uniaxial ( - ) 

Birefringence:

0.007 - 0.009

Dispersion:

n/a

Pleochroism:

None

Occurances

Geological Setting:

Typically in regionally metamorphosed rocks, especially marbles, calcareous gneisses, granulites, and greenschists. Also in skarns, some pegmatites, pneumatolytically or hydrothermally altered mafic igneous rocks, and ejected volcanic blocks.

Common Associations:

Plagioclase, Garnet, Pyroxenes, Amphiboles, Atitanite, Zircon.

Common Impurities:

Fe, Ca, K, S

Type Locality:

Pianura, Phlegrean Fields, Naples Province, Phlegrean Volcanic complex, Campania, Italy

Year Discovered:

1866

View mineral photos:

Marialite Mineral Photos and Locations

More Information

Mindat.org
Webmineral.com

Marialite was first described in 1866 for an occurrence in the Phlegrean Volcanic complex, Campania, Italy. Marialite was named in 1866 by German mineralogist Gerhard vom Rath (1830-1888) in honor of his wife, Maria Rosa vom Rath (1830-1888).

Marialite is a member of the Scapolite Group of minerals that includes Kembleite, Marialite, Meionite and Silvialie. Marialite also belongs to the Marialite-Meionite series. Marialite is the sodium chloride rich end member and Meionite is the calcium carboniate rich end member with Wernerite as a possible intermediate member of the series. Although Wernerite is mostly an obsolete name now it may be deserving of species status (see Dana, 8th Ed.).

Scapolite is generally used as a mineral species name but actually refers to the Marialite-Meionite series, not an individual mineral name or the full Scapolite Group, so excludes Kembleite and Silvialite. The name Scapolite is now often used as a generic term when the exact chemical composition of a specimen in the Marialite-Meionite solid solution series has not been determined. Distinguishing the Scapolite minerals from each other is difficult as they differ only slightly in density and index of refraction, increasing in both with increasing calcium content. It is because of this closeness in properties and yet seemingly very different chemistries that Scapolite has had its share of pseudonyms. Wernerite was the most common alternate name for the Scapolite series, but now it has mostly disappeared from use. A few other names such as Mizzonite and Dipyre as well as Marialite and Meionite have been used as names for the entire Scapolite series.

Marialite commonly fluoresces orange to bright yellow or red under SW and/or LW UV light.

Most specimens are intermediate in the series; some localities for highly sodic materials include: at Pianura, west of Naples, Campania, Italy. From Russia, in the Slyudyanka region, near Lake Baikal, Siberia. In the USA, at Hamburg and Franklin, Sussex County, New Jersey; at Natural Bridge, Je®erson County, Macomb, St. Lawrence County, and Olmsteadville, Essex County, New York; from French Creek, Chester County, Pennsylvania. In Canada, at Bear Lake, Pontiac County, Quebec, and Bancroft, Ontario. From the La Panchita mine, near Ayoquezco, Oaxaca, Mexico. From Serra da Chibita, Rio Pardo, Minas Gerais, Brazil. At Tsarasaotra and Betroka, Madagascar. From Mpwapwa, Morogoro region, Dodoma, Tanzania. In the Mogok district, Myanmar (Burma).

Marialite gems for sale:

We have not photographed our Marialite gems yet. Please check back soon.