[Rockhounds] Life Helps Make Almost Half of All Minerals on Earth

[Tim Fisher]

Probably irrelevant but note that many sources (informed and uninformed) designate a "thunderegg" as a "geode" (or a class of geode), even though they are formed by entirely different processes than your "average geode" and are inappropriately called "geodes" in many sources, including some that should have known better. But it may be interesting to lump them in and see where they fall...

Tim Fisher
Http://OreRockOn.com 
Email nospam at orerockon.com

-----Original Message-----
From: Rockhounds [mailto:rockhounds-bounces at rockhounds.drizzle.com] On Behalf Of linda at middleearthminerals.com
Sent: Saturday, July 02, 2022 10:41 AM
To: 'Rockhounds at drizzle.com: A mailing list for rock and gem collectors'
Subject: Re: [Rockhounds] Life Helps Make Almost Half of All Minerals on Earth

This is totally consistent with many (possibly most?) geological definitions since they incorporate the formation process.  For example, a cirque is formed by the head of a glacier.  If it looks similar to a cirque but was not formed by a glacier, then it isn't truly a cirque.

To bring it down to our interests, I believe even the humble geode requires a definition acknowledging formation.  If you don't consider formation, how do you exclude carved vugs, for example?  In my opinion, a geode can be exposed by carving if it could eventually have weathered out as an intact, roughly spherical unit.  This requires that it have some internal structure (often layers of quartz or agate) that produces a "rind" tough enough to keep it together while weathering out.  Geodes can form in both sedimentary and igneous environments.  (I even have one that may be metamorphic.)  

Why define a geode?  I used to exhibit at a county fair and had to guess at what the judges would consider a geode to be.  It turned out to be an intriguing and difficult definition.

-----Original Message-----
From: Rockhounds <rockhounds-bounces at rockhounds.drizzle.com> On Behalf Of Kreigh Tomaszewski
Sent: Saturday, July 2, 2022 6:13 AM
To: Rockhounds at drizzle.com: A mailing list for rock and gem collectors <rockhounds at rockhounds.drizzle.com>
Subject: [Rockhounds] Life Helps Make Almost Half of All Minerals on Earth

The impact of Earth’s geology on life is easy to see, with organisms adapting to environments as different as deserts, mountains, forests and oceans. The full impact of life on geology, however, can be easy to miss.

A comprehensive new survey of our planet’s minerals now corrects that omission. Among its findings is evidence that about half of all mineral diversity is the direct or indirect result of living things and their byproducts. It’s a discovery that could provide valuable insights to scientists piecing together Earth’s complex geological history — and also to those searching for evidence of life beyond this world.

In a pair of papers published today in American Mineralogist, researchers Robert Hazen, Shaunna Morrison and their collaborators outline a new taxonomic system for classifying minerals, one that places importance on precisely how minerals form, not just how they look. In so doing, their system acknowledges how Earth’s geological development and the evolution of life influence each other.

Their new taxonomy, based on an algorithmic analysis of thousands of scientific papers, recognizes more than 10,500 different types of minerals.
That’s almost twice as many as the roughly 5,800 mineral “species” in the classic taxonomy of the International Mineralogical Association, which focuses strictly on a mineral’s crystalline structure and chemical makeup.

“That’s the classification system that’s been used for over 200 years, and the one that I grew up with and learned and studied and bought into,” said Hazen, a mineralogist at the Carnegie Institution for Science in Washington, D.C. To him, its fixation on mineral structure alone has long seemed like a monumental shortcoming.

https://www.quantamagazine.org/life-helps-make-almost-half-of-all-minerals-20220701/
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