I sort of like the point and click approach, upload data to your
computer, and the pieces are untouched. I would assume it's not
cheap, judging by the built in security features.
Yes, x-ray fluorescence is a highly accurate test so far as it can
go. Note that it tests the surface layer, not the whole bulk of the
metal, so electroplated or surface depleted pieces can fool them. But
other than that limit (shared by most other non-destructive tests),
these things can be accurate to the parts per million level.
The trouble is, they’re not generally jewelers tools. The reason?
You can buy a full featured full size laser welder for less than
these things. (the one time I tracked down a price, when one was
offered for sale on ebay, I came up with a price range of from 35 to
45 thousand dollars. That’s do-able for a major lab, or a refinery or
larger manufacturer who needs that level of in house control over
metal quality and alloy composition, or the like. But not for most