Cryolite ore

Cryolite is name after the Greek words kryos – Ice, and lithos – stone, based on the typical icy

-white color of this ore.

Cryolite is an unusual ore with an interesting history. It was commercially mined in large quantities in Greenland since the mid-1800’s, and this one locality produced almost the entire source of collectors specimen. Greenland was the only major source of cryolite anywhere in the world. The mine is now closed although some stock-piled ore is still being exported. Cryolite’s economic importance was as a flux for the production of aluminum, but its significance became entirely diminished once it was able to be synthesized. This made the ore operation no longer necessary, and mining and production of Cryolite was entirely stopped.

The cryolite ore was used as a solvent for the aluminium-rich ore bauxite which is a combination of various oxides of aluminium.
Cryolite is usually lightly colored, and it commonly associated with contrasting dark brownish yellow Siderite. The Siderite may also be in microcrystals covering the Cryolite, making it appear yellow or brown. Cryolite has a very low refractive index, similar to water, and therefor if transparent pieces put in water, they will blend right in and be hard to distinguish in the water.

It is difficult to separate atoms of aluminium and oxygen during smelting, to produce pure liquid aluminium. The addition of cryolite in the process acts as a flux and cuts in half the temperature required to obtain aluminum. The savings in energy expenditure, and money spent, are considerable. The ore was considered so strategic during World War II that American troops were stationed in Greenland to protect the cryolite ore.

Cryolite is now too rare for general commercial use and has been largely replaced by synthetic sodium aluminium fluoride.

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