[Rockhounds] The Color of Rare Earth Minerals

[gary brown]

Funny man.

Thanks!

GcB

-----Original Message-----
From: Rockhounds <rockhounds-bounces at rockhounds.drizzle.com> On Behalf Of
Axel Emmermann
Sent: Wednesday, June 12, 2019 5:09 PM
To: 'Rockhounds at drizzle.com: A mailing list for rock and gem collectors'
<rockhounds at rockhounds.drizzle.com>
Subject: Re: [Rockhounds] The Color of Rare Earth Minerals

Samarium causes light green color in 3+ state in aragonite and fluorite. In
fluorite it can change to violet-grey due to sunshine and reduction to 2+
state.
Most color in minerals is caused by d-orbitals in transition metals like
iron, nickel, cobalt, copper, etc...
In REE, the d-orbitals are shielded by 5f orbitals. But there is STRONG
fluorescence in MANY minerals that contain REE. They cover the complete
spectrum with their emissions including NIR and deep UV.

Say hi to Sushi (whoever that is)
Axel

-----Oorspronkelijk bericht-----
Van: Rockhounds <rockhounds-bounces at rockhounds.drizzle.com> Namens gary
brown
Verzonden: woensdag 12 juni 2019 21:16
Aan: 'Rockhounds at drizzle.com: A mailing list for rock and gem collectors'
<rockhounds at rockhounds.drizzle.com>
Onderwerp: [Rockhounds] The Color of Rare Earth Minerals

My son (originally a chemist...now a computer geek) asked me an interesting
question over lunch (which he paid for!  Yay!):

Are "rare-earth" minerals colorful as a rule, or are they more
blue-grey-black?

"Hmmm", I said (munching down another hunk of sushi),  "I'll ask the Hive
Mind..."

And so... here I am!

Gary Brown



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