SH wrote:

you have to look for x-ray fluorescence spectrometer
They are not the sort of thing you will find on Ebay.

Well, not for cheap anyway

https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2499334.m570.l1313&_nkw= xrf&_sacat=185238

Cody uses one in his mine, and Ben demonstrates one here

https://youtu.be/KdfHVcU8U7U