Nepheline

Real mineral · uncommon · (Na,K)AlSiO₄

A feldspathoid of alkaline magmas, formed where there was too little silica for feldspar to crystallise. It never occurs beside quartz, which makes it a reliable marker of silica-poor rock.

Identity

Formula

(Na,K)AlSiO₄

Chemical class

silicate

Also known as

Eleolite

Crystallography

Crystal system

hexagonal

Habits

prismatic, massive, granular

Fracture

conchoidal

Physical properties

Mohs hardness

6

Density

2.59 g/cm³

Luster

vitreous, waxy

Colors

white, gray, brown, brownish gray, reddish white

Streak

white

Transparency

transparent, translucent, opaque

Geology

Origins

igneous, volcanic

Host rocks

syenite, phonolite

Associated minerals

Aegirine, Cancrinite, Sodalite, Hauyne

Geography

Norway, Russia, Canada

Classification

Rarity

uncommon

Gem quality

No

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