How do I identify Cryolite?

Cryolite can be identified by its hardness of 2.5 on the Mohs scale, Colourless color. Look for these key characteristics when examining specimens.

What color is Cryolite?

Cryolite typically appears in Colourless, white, brown, grey, black, colourless in transmitted light. Color can vary depending on impurities and formation conditions.

How hard is Cryolite?

Cryolite has a hardness of 2.5 on the Mohs scale. This makes it a soft mineral that can be scratched easily.

Cryolite

A variety of Minerals

What is Cryolite?

Cryolite (Na3AlF6, sodium hexafluoroaluminate) is an uncommon mineral identified with the once-large deposit at Ivittuut on the west coast of Greenland, depleted by 1987.

Uses & Applications

Molten cryolite is used as a solvent for aluminium oxide (Al2O3) in the Hall–Héroult process, used in the refining of aluminium. It decreases the melting point of molten (liquid state) aluminium oxide from 2000 to 2500 °C to 900–1000 °C, and increases its conductivity thus making the extraction of aluminium more economical. Cryolite is used as an insecticide and a pesticide. It is also used to give fireworks a yellow color.

Optical Properties

Refractive Index: 1.338-1.339
Birefringence: 0.001
Optical Character: Biaxial positive

Cryolite Market Value Calculator

Estimate the market value of Cryolite using size, quality, and finish. This preview calculator is for quick context and is not a formal appraisal.

Cryolite Localities Map

See where Cryolite is found with a localities map, collecting zones, and geology context. Generate a sample map preview below.

Map preview

North ZoneCentral RidgeSouth Basin

The Meaning

In traditional folklore, cryolite was considered a stone of protection. During ancient times, people believed that cryolite warded off evil spirits, so they would wear it around their chests, often set in gold, to deter phantoms and thus protect themselves.

Key Characteristics

Characteristics of Cryolite

Cryolite occurs as glassy, colorless, white-reddish to gray-black prismatic monoclinic crystals. It has a Mohs hardness of 2.5 to 3 and a specific gravity of about 2.95 to 3.0. It is translucent to transparent with a very low refractive index of about 1.34, which is very close to that of water; thus if immersed in water, cryolite becomes essentially invisible.

Quick Facts

Physical Properties

Color: Colourless, white, brown, grey, black, colourless in transmitted light
Hardness (Mohs): 2.5
Density: 2.973 - 2.9732 g/cm³
Streak: White