Pectolite

Real mineral · uncommon · NaCa₂Si₃O₈(OH)

Needle-sharp sprays lining cavities in basalt; the fibres are brittle enough to splinter into the skin when handled. Its blue Dominican variety, larimar, is the only pectolite cut as a gemstone.

Identity

Formula

NaCa₂Si₃O₈(OH)

Chemical class

silicate

Mineral group

Rhodonite

Also known as

Larimar (blue variety)

Crystallography

Crystal system

triclinic

Habits

acicular, fibrous, massive

Fracture

splintery

Physical properties

Mohs hardness

5

Density

2.86 g/cm³

Luster

silky, vitreous

Colors

white, gray, light pink, light green

Streak

white

Transparency

translucent, opaque

Geology

Origins

igneous, hydrothermal

Host rocks

basalt, serpentinite

Associated minerals

Prehnite, Calcite, Natrolite, Analcime

Geography

Dominican Republic, Canada, USA

Classification

Rarity

uncommon

Gem quality

Yes

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