The Mineral marialite

Marialite is the sodium-rich end member of the Scapolite series. It is very similar and often indistinguishable from Meionite, the other end member of the series. Intermediary forms of Marialite and Meionite are frequent, and these are classified simply as Scapolite. Marialite is named after Maria Rosa von Rath, the wife of German mineralogist Gerhard von Rath (1830-1888).

Chemical Formula

Na₄(Al₃Si₉O₂₄)Cl

Color

White, gray, colorless, cream, yellow, bluish-gray, and purple. Less commonly blue, brown, green, red, and pink.

Crystal System

Tetragonal

Properties

Streak White

Hardness 5.5 - 6

Transparency Transparent to opaque

Specific Gravity 2.5 - 2.6

Luster Vitreous to dull

Cleavage 2,2

Fracture Conchoidal, uneven

Tenacity Brittle

Other ID Marks Often fluorescent, sometimes brightly. Colors include white, yellow, and pink. Fluorescence may be present both in shortwave and longwave.

Crystal Habits

Crystals are often short and stout with a slightly angled or pyramidal termination, or long and prismatic. Crystals can be very large and fat, and are often intergrown in groups of such crystals or are columnar. Also grainy, massive, and crudely as formed crystal masses. Prismatic crystals are often striated.

3D Crystal Atlas

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Additional Information

Composition Sodium aluminum chloro-silicate

In Group Silicates; Tectosilicates

Striking Features Crystal habit, environment, and fluorescence

Environment In volcanic rock such as basalt, and in metamorphic rocks such metamorphosed limestones, skarns, gneisses, and hornfels. Also in granite pegmatites.

Rock Type Igneous, Metamorphic

Other Names

Mizzonite

Noteworthy Localities

The two Scapolite members often occur together and are not usually individually distinguished. See Scapolite for a comprehensive list of localities general to the Scapolite series.

Common Mineral Associations

Diopside, Calcite, Biotite, Phlogopite, Titanite, Hornblende, Actinolite, Tremolite, Almandine, Microcline, Albite, Muscovite

Distingushing Similar Minerals

Meionite - Difficult to distinguish without chemical analysis.
Feldspars - Often form in different crystal habits, lacks fluorescence.
Nepheline - Different cleavage, lacks fluorescence.

marialite Photos

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