Scapolite

Real mineral · uncommon · (Na,Ca)₄(Al,Si)₁₂O₂₄(Cl,CO₃,SO₄)

A sodium calcium aluminium silicate group forming in metamorphic marbles and skarns. Displays strong orange fluorescence. Some specimens show chatoyancy. A common alteration product of plagioclase feldspar in metamorphic rocks.

Identity

Formula

(Na,Ca)₄(Al,Si)₁₂O₂₄(Cl,CO₃,SO₄)

Chemical class

silicate

Also known as

Wernerite, Meionite (calcium-rich end), Marialite (sodium-rich end)

Crystallography

Crystal system

tetragonal

Habits

prismatic, massive

Fracture

conchoidal

Physical properties

Mohs hardness

6

Density

2.65 g/cm³

Luster

vitreous

Colors

yellow, orange, pink, purple, colorless, gray

Streak

white

Transparency

transparent, translucent

Geology

Origins

metamorphic

Host rocks

marble, skarn, gneiss

Associated minerals

Calcite, Diopside, Garnet, feldspar

Geography

Tanzania, Myanmar, Canada, Brazil, Madagascar

Classification

Rarity

uncommon

Gem quality

Yes

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