[Rockhounds] Super-deep more perovskite

[Dennis Buffenmyer]

On 3/9/2018 12:26 PM, pmodreski at aol.com wrote:
> Glenn, I think the simple answer is that these transformations back to ordinary low-pressure mineral forms occur very quickly, and that it is only under exceptional situations, such as a crystal being enclosed within a diamond, that the high-pressure minerals are SOMETIMES (very rarely, sometimes never) preserved.
>
>
> Pete
> 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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> The spinel-structure polymorph of olivine, ringwoodite,
Ok, here comes my question. at least we have a new name for a structural 
difference resulting in a new mineral name. It is confusing enough that 
the naming of minerals seems broad in some areas, and others are tightly 
confined. Am I to assume they have given a mineral name to a particular 
structure?? With perovskite as a mineral being Calcium titanium oxide, 
the usage of calcium silicon oxide as perovskite is confusing.
And if it only exists in a fluid phase or at least a "toothpaste" phase 
then what is the relevance of "crystal" symmetry?
I realize this is all probably a geology 101 question, or possibly an 
igneous/metamorphic rocks 101 question, but I hope I am not belaboring 
the point here. Bottom line, in the example the silicon does not 
magically transform into Titanium as the mixture can not exist in a 
crustal atmosphere? The event of note is that we have a high pressure 
mineral incapable of existing at normal pressures contained within a 
mineral that is stable at a crustal pressure?
Sorry folks
Dennis Buffenmyer