Crystal Vesuvianite

Chemical Formula

Ca₁₀Mg₂Al₄(SiO₄)₅(Si₂O₇)₂(OH)₄

Composition

Basic calcium magnesium aluminum silicate.
 

Variable Formula

Color

Brown, green, yellow. Less commonly pink, purple, orange, maroon, red, and blue. Multicolored shades of green or pink/purple and green are rare.

Streak

White

Hardness

6.5

Crystal System

Tetragonal

Crystal Forms 
and Aggregates

In short prismatic crystals with rectangular cross-section, occasionally with a pointed termination and sometimes doubly terminated. Crystals may be short and stubby, and may also be elongated or pyramidal. They are less commonly pseudo-octahedral, or with termination faces that appear dodecahedral. Also columnar, radiating, acicular, grainy, compact, massive, and encrusting. Crystals are sometimes striated.
 

Transparency

Transparent to opaque

Specific Gravity

3.3 - 3.5

Luster

Vitreous (sometimes resinous)

Cleavage

3,1

Fracture

Conchoidal to uneven

Tenacity

Brittle

In Group

Silicates; Sorosilicates

Striking Features

Crystal habits, localities, and frequent association with Grossular Garnet.

Environment

Most often in metamorphic rocks especially in metamorphosed limestones, hornfels, skarns, and Serpentines. Less commonly in igneous rocks in pegmatites.
 

Rock Type

Igneous, Metamorphic

Popularity (1-4)

2

Prevalence (1-3)

2

Demand (1-3)

2