[decimon]

I see that the National Science Foundation is also covering this and with some neatsy pictures.

Like this one:
New measurements of quartz abundance from EarthScope data show that mountains are quartz-rich (red-orange colors). The Great Plains, Columbia Basin and Great Valley have little or no quartz (blue-green colors).

Credit: Lowry & Perez-Gussinye

Viscous Cycle: Quartz is Key to Plate Tectonics

[Duchess47]

Crystal Peak, NV. Whole mountain of crystals.

[Ron C.]

Funny that the map doesn't show much red or orange around LA and much less near San Fran. Lots of it in AZ and NM where there is never a quake.

It is the fault lines where most quakes originate, and they are all deep rifts in the plate techtonics, so it is hard for me to jump on this bandwagon and blame quartz.

BTW, decimon - you're right and I was wrong. Quartz is 7 to 7.5 - not 9. My memory from reading that scale was quite faulty! LOL But, then at my age, I have more faults seemingly every day...