I think most of the radiation in that sample is alpha. The gamma peak they measured the highest count for is the 59 keV from Am-241. The invisible monster they can't detect is the 5,486 keV alpha generated by that same isotope. That's the main hazard there—should someone remove the sample from the glass vial and somehow get significant exposure to dust. (Otherwise, the glass is more than sufficient shielding).

Wire wrap jewelry right now is a big thing

Nobody needs to grind a thing that would be such a waste, it's a very brittle silicate. That link is really interesting however it says you pretty much have to eat the stuff for it to have any ill effect. Sand for breakfast, anyone?