Minerals are physical objects, rooted in time and formed through complex planetary processes.

So why don’t scientists classify them that way? A philosopher and two Earth scientists recently asked that question in the journal PNAS — and proposed a solution that could lead to a new way to categorize minerals.

The International Mineralogical Association is the authority on minerals, and the group publishes a list of minerals similar to the periodic table.

But, the researchers say, that classification isn’t useful to a wide range of scientists.

That’s because it relies on approved formulas — combinations of elements — to describe minerals like quartz (formula SiO2).

That formula represents an ideal that is rarely found in reality, the authors say. It doesn’t describe how the mineral was formed, what trace elements it might contain or when it was formed.

“Ideal quartz does not exist in nature (or in the laboratory), because every quartz specimen has myriad trace and minor elements, isotopic variations, fluid and solid inclusions, structural defects, crystal size and shape,” and other attributes, they write. And every quartz specimen has a history that isn’t represented in the formula.

To solve that problem, and make mineral classification more relevant to researchers in paleontology, planetary science and other fields, they suggest a new classification system rooted in time.

They call for a “bootstrap” approach that involves collecting and analyzing 200 years of research on all known minerals and using it to inform a new, open-access repository that includes hundreds of attributes.

It’s a bold proposition, and one that could take decades. But it will be worth it, the authors say.

“Minerals are the most durable, information-rich objects we can study to understand our planet’s origin and evolution,” said co-author Robert Hazen, a mineralogist at the Carnegie Institution for Science, in a release. “They provide a time machine to go back and understand what was happening on our planet and other planets in our solar system millions or billions of years ago.”