[Rockhounds] Super-deep diamond provides first evidence in nature of Earth's fourth most abundant mineral

[Glenn Wimpee]

Very interesting.

I would like to learn how, why, and what these minerals would morph into in "normal" surface conditions and an estimated time frame for the morphing changes to complete.

Thanks all for sharing!

Glenn Wimpee
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From: Rockhounds <rockhounds-bounces at rockhounds.drizzle.com> on behalf of pmodreski at aol.com <pmodreski at aol.com>
Sent: Thursday, March 8, 2018 10:52 AM
To: rockhounds at rockhounds.drizzle.com
Subject: Re: [Rockhounds] Super-deep diamond provides first evidence in nature of Earth's fourth most abundant mineral

Ah... (interesting, thanks, Kreigh!).  The article blurb doesn't seem to go on to clarify, what the "first three most abundant minerals on earth" are.  That's always an interesting debate!


When we talk about the Earth's crust, we always say that it's quartz as most abundant, but then there's an extra argument about whether it's quartz or feldspar, and whether feldspar should be counted as a bunch of separate mineral species... but the crust is so thin, that neither of them ranks as abundant enough, for the whole earth.


Then, I normally tell people that olivine is really the most abundant mineral, since it makes up most of the mantle.  But, that's only the upper mantle, and once into and below the transition zone, other, denser high-pressure phases become dominant.


The spinel-structure polymorph of olivine, ringwoodite, is believed to be the most abundant mineral within the Transition Zone of the mantle. There is also wadsleyite, another spinel-structure form of Mg2SiO4.  But in the lower mantle, bridgemanite, a pyroxene composition, (Mg,Fe)SiO3, with pyroxene structure, is said to be the most abundant mineral in the lower mantle, and thus the overall most abundant mineral averaged over the whole earth.  Also present there is ferro-periclase, a dense form of MgO also containing some FeO.  And then there is the subject of the present article, the CaSiO3-composition, perovskite structure mineral.


And then, one could debate as to whether the nickel-iron alloy phase(s) in the solid part of the core (outer core) count as minerals too, and how abundant they are relative to the dense silicates in the mantle.


So, it will be interesting to see what they (or whoever) actually ranks as "1st, 2nd, 3rd, and 4th most abundant" minerals in the earth!


Does anyone find a list of these "most abundant minerals in the Earth", in order?


Pete




-----Original Message-----
From: Kreigh Tomaszewski <kreigh at gmail.com>
To: Rockhounds at drizzle.com: A mailing list for rock and gem collectors <rockhounds at rockhounds.drizzle.com>
Sent: Thu, Mar 8, 2018 7:29 am
Subject: [Rockhounds] Super-deep diamond provides first evidence in nature of Earth's fourth most abundant mineral

For the first time, scientists have found Earth's fourth most abundantmineral—calcium silicate perovskite—at Earth's surface."Nobody has ever managed to keep this mineral stable at the Earth'ssurface," said Graham Pearson, a professor in the University of Alberta'sDepartment of Earth and Atmospheric Sciences and Canada Excellence ResearchChair Laureate. He explained the mineral is found deep inside Earth'smantle, at 700 kilometres.Read more at:https://phys.org/news/2018-03-super-deep-diamond-evidence-nature-earth.html#jCp_______________________________________________Rockhounds mailing listSubscription Services:  http://rockhounds.drizzle.com/mailman/listinfo/rockhounds_rockhounds.drizzle.comList Usage Policy: http://Tomaszewski.net/Kreigh/Rockhounds/Rockhounds.shtml
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