What makes Apophyllite radioactive?

Submitted by Anonymous on Thu, 2013-03-07 20:49

I've been reading up on my mineral sample of Apophyllite. Apparently there are 3 different kinds - KF, KOH, and NaF. KF and KOH are mildly radioactive, whereas NaF is not.

My hunch is that the K is where it's at...the potassium present in the KF and KOH versions, which isn't found in the NaF. Am I right so far?

If so, would the composition of that potassium be similar to that found in bananas, etc.: ~ .1% K-40, and would that specifically be the cause of the mild radioactivity of Apophyllite KF and KOH?

Thanks in advance!

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Yup, you're right. It

Submitted by Anonymous on Thu, 2013-03-07 21:19.

Yup, you're right.

It should have the same general isotopic concentrations found in nature so it should be 0.012% K-40.

Diemos

Yes, it's the potassium

Submitted by bandstra on Fri, 2013-03-08 12:57.

Diemos is absolutely right; all potassium contains a small, constant fraction of the primordial radionuclide K-40, which was formed long ago in the stellar processes that created all of the elements.

As a demonstration of this, please look at my Measurement of radiation from potassium chloride (KCl). Table salt (NaCl) would not be radioactive like salt substitute (KCl).

Mark [BRAWM Team Member]

Thank you both! I'm pleased I

Submitted by Anonymous on Fri, 2013-03-08 20:42.

Thank you both!
I'm pleased I got this educated guess right.