Mineral description : Phenakite

Mineral class Silicates : Beryl - tourmaline group

Chemical formula BeCO₂SiO₄

Crystal system Trigonal / hexagonal

Habitus Short prismatic or romboedric crystals, oftly twinned. Also granular and acicular habits and as radiating fibrous spherulites.

Cleavage Distinct, fracture conchoidal.

Hardness 7.5-8

Density 2.93-3

Color Usually colorless or white, but nuances in yellow, pink and brown exists.

Streak white

Luster Vitreous.

Description

Occurance Forms in hydrothermal veins, granitic igneous rocks and pegmatites. It can also occur in schist with beryl.

Associates In schists : Beryl, chrysoberyl, topaz, quartz, apatite.
In pegmatites : Beryl, bertrandite, euclas, quartz.

Notes Insoluble in acids and infusible.

Locations A rare mineral in Sweden.

Långban,Värmland. As up to 8 mm crystals in calcite veins in hematite. Also in tilasite scarn with svabite and romeite.
Jakobsbergsgruvan, Nordmark.
Selsvitberget, Bollstabruk. Small crystals (<2mm) and masses at the rim of altered beryl.

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Last changed : 1998-03-07

Mineral class	Silicates : Beryl - tourmaline group
Chemical formula	BeCO₂SiO₄
Crystal system	Trigonal / hexagonal
Habitus	Short prismatic or romboedric crystals, oftly twinned. Also granular and acicular habits and as radiating fibrous spherulites.
Cleavage	Distinct, fracture conchoidal.
Hardness	7.5-8
Density	2.93-3
Color	Usually colorless or white, but nuances in yellow, pink and brown exists.
Streak	white
Luster	Vitreous.
Description
Occurance	Forms in hydrothermal veins, granitic igneous rocks and pegmatites. It can also occur in schist with beryl.
Associates	In schists : Beryl, chrysoberyl, topaz, quartz, apatite. In pegmatites : Beryl, bertrandite, euclas, quartz.
Notes	Insoluble in acids and infusible.
Locations	A rare mineral in Sweden. Långban,Värmland. As up to 8 mm crystals in calcite veins in hematite. Also in tilasite scarn with svabite and romeite. Jakobsbergsgruvan, Nordmark. Selsvitberget, Bollstabruk. Small crystals (<2mm) and masses at the rim of altered beryl.