Australian Facetors' Guild Limited

I've seen pictures in Facet Talk of fission holes on Zircon caused, I assume, by the fission of the uranium atoms trapped in its crystal lattice.  

I've also read how Zircons are used to measure the age of the host rock using the half life of said uranium and the ratio of U238 to U236 (I think they are the right numbers).

Can anyone tell me if Zircon is more radioactive than the usual background radiation in our environment.

Given that swarf is very finely ground stone dust, meaning there is less mass to stop protons, neutrons and smaller sub-atomic particles released by fission, does Zircon swarf need any special handling apart from being tipped on the garden when I empty my waste water bucket?  After all the finer the particle the greater the opportunity for the release of  metals from the powder.

Regards

Gordon