Here’s how Earth’s minerals are helping scientists reconstruct history of planet — and find alien life too

WASHINGTON — There are over 6,000 known minerals on Earth. At least, that’s what the International Mineralogical Association (IMA) says. But a new study says that number might be off by quite a bit.

The IMA has been keeping track of minerals since 1958. Its database currently holds information about over 6,000 known minerals and their chemical compositions. But according to a new study by The Carnegie Institution for Science, there’s almost double the number of different types of minerals on Earth — around 10,500.

This is the first time scientists have been able to definitively count how many minerals exist on our planet.

The Carnegie Institution for Science is leading a study to map the origins and diversity of every known mineral on Earth. They analyzed tens of thousands of samples from all over the world and found dozens of new minerals with unique properties not previously recognized by science. How did they come to be?

​​Scientists say the variety of minerals we see today can be linked back to the early processes that led to their formation. Now we have evidence that much of our current mineral diversity was established during the first 250 million years after Earth formed. The earliest minerals on Earth (like zircon crystals) are dated to have been formed 4.4 billion years ago, with some 296 known minerals that pre-date Earth itself. 97 types of minerals come from meteorites.

Pyrite, the mineral world’s champion of diverse origins
Nature has used 21 different ways over the last 4.5 billion years to create pyrite (aka Fool’s Gold) — the mineral world’s champion of diverse origins. Pyrite forms at high temperature and low, with and without water, with the help of microbes and in harsh environments where life plays no role whatsoever. (Credit: ARKENSTONE/Rob Lavinsky)

“For example, more than 80% of Earth’s minerals were mediated by water, which is, therefore, fundamentally important to mineral diversity on this planet. By extension, this explains one of the key reasons why the Moon and Mercury and even Mars have far fewer mineral species than Earth,” says ​​Dr. Hazen, Staff Scientist with the Earth and Planets Laboratory at Carnegie explains in a statement.

When water first appeared on Earth, 350 types of minerals were created in near-surface marine environments. Some formed through simple chemical reactions, while others formed as a result of biological processes. These minerals were created during what we now consider an important formative period in Earth’s history.

The current system of mineral classification is based on the physical properties of the mineral structure and chemical composition. This system is not always effective at identifying the unique characteristics of each mineral’s origin, and how minerals created new species.

Understanding the diversity of minerals could help scientists figure out how certain elements were formed and how they interact with each other. Moreover, scientists could learn how Earth’s climate has changed over time, and also how it’s going to change in the future.

The study will help researchers reconstruct the history of life on Earth, guide their search for new minerals and ore deposits, predict possible characteristics of future life, and aid in the search for habitable planets and extraterrestrial life.

Opalized ammonite
A beautiful example from Alberta, Canada of a biomineral — an intersection of minerals and life. (Credit: ARKENSTONE/Rob Lavinsky)

It’s a massive undertaking. Discovering new species of minerals ​​is like trying to count all the stars in the sky — you can’t do it without some special tools.

Imagine you pick up your favorite type or kind of rock. This rock may have had origins from space or home-grown origins from the crust of our very Earth. In particular Pyrite, Fool’s Gold has an incredibly diverse background story. Pyrite has 21 different ways it can form.

The next time you pick up a pyrite and hold it up to the light in a gift shop at a state park, think of the origins of this pretty, seemingly simple rock. Those hard-cut, clean, and attractive angles sprouting from a rocky bed feels as good as holding a real nugget of gold, but knowing how it may be a key to understanding the future and past is worth its weight.

The research is published in American Mineralogist.

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