TWO CENTURIES OF MINERAL CLASSIFICATION: IS THERE MORE THAN ONE VALID SYSTEM?

Proposals to organize mineral “species” into coherent classification systems have been a recurrent theme in the history of mineralogy. Successful systems have incorporated several aspects: They must be comprehensive, embracing a wide range of natural condensed phases. They must be unambiguous—providing reproducible identifiers and unique names for each type of mineral. They must be sufficiently flexible to embrace new kinds of materials and properties when they are discovered. And, ideally, they should be solidly grounded in a theoretical framework that reinforces the gestalt of the Earth and planetary science community.

Key events in the history of mineral classification include the 1850 publication of the third edition of James Dwight Dana’s System of Mineralogy (the original elaboration of what is known as the ‘Dana System’), Mendeleev’s development of the Periodic Table of elements, and the widespread adoption of crystal structure analysis by x-ray diffraction. The resulting modern mineral classification system, as overseen by the International Mineralogical Association (IMA), is based on unique combinations of end-member chemical compositions and idealized crystal structures.

Today, as large and growing open-access mineral data resources become available, the opportunity exists to amplify and modify the Dana system by incorporating physical and chemical attributes that point to processes of mineral formation in the context of planetary evolution.