Crystal Albite

Chemical Formula

NaAlSi₃O₈

Composition

Sodium aluminum silicate, often with the sodium partially replaced by calcium or potassium. 
 

Color

White, colorless, cream, light yellow, light blue, light green, pale red, light brown, gray. Some Albite is iridescent with schillers.

Streak

White

Hardness

6 - 6.5

Crystal System

Triclinic

Crystal Forms 
and Aggregates

Crystals are usually flat and bladed, and often in compact groupings. Also occurs as tall prismatic and short, stubby, tabular crystals. These crystals are usually in groupings, and rarely occur singly on a matrix. Crystal twins are common. Other forms are grainy, massive, columnar, rosette, and coxcomb. Crystals are sometimes striated.

Click here for more detailed information on the crystal structure of the Feldspars.
 

Transparency

Transparent to translucent

Specific Gravity

2.6 - 2.63

Luster

Vitreous to pearly

Cleavage

2,1 - basal ; 2,1 - prismatic ; 3,1 - pinacoidal. The cleavage angle is about 90º.

Fracture

Subconchoidal to uneven

Tenacity

Brittle

Complex Tests

Soluble in hydrofluoric acid

In Group

Silicates; Tectosilicates; Feldspar Group

Striking Features

Crystal habits, cleavage, hardness, and color

Environment

Most often in granite pegmatite, also in metamorphic rocks and sedimentary conglomerates.

Rock Type

Igneous, Sedimentary, Metamorphic

Popularity (1-4)

2

Prevalence (1-3)

1

Demand (1-3)

1