New Classification Reveals Just How Many Ways Minerals Form

Minerals are part of the environment in which they are formed. Key features of the ancient Earth or other planets can be revealed with the correct approach.

For a long time, geologists have classified minerals by their unique combinations of chemical formula and crystal structure. The classification system doesn't take into account how the minerals form.

"What you don't get from this very quantifiable, very definable taxonomy of mineral species is context," says a mineralogist and planetary scientist. Morrison and her colleagues wrote two papers in American Mineralogist in order to make up for the old system of growing and transforming minerals.

The researchers report that the shiny golden mineral can be formed in 21 different ways. The chemical fingerprints of each way are created by trace contaminants and radioactive elements. Morrison wants to use this kind of detail to find out how the planet formed, and if life could have been involved.

Without water, 80 percent of the minerals wouldn't exist. Changing Ice Age water levels in a cave in southern China are reflected in the crystallised form of calcite. The mineral can be formed in many ways.

After other remains rot away, a mixture of water and silica can cause fossils such as this one to grow. The minerals formed as a result of biological processes.

Close to half the planet's mineral types were formed directly or indirectly by life's emergence on Earth. The deep green malachite was formed after the bacterium began releasing oxygen.

Although the concept of mineral evolution is not new, this proposed framework is a way to get people to think differently about mineralogy and possibly offer avenues for research that will make the field more robust and interesting.

The University of Colorado Boulder mineral physicist, who was not involved, says she is going to incorporate this modified taxonomy in her classroom. She sees it as a way to add some flexibility to the original, rigid mineral classifications.

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