Hi Will
I think I did not take the pics clear enough so it seems leading you to a wrong judgement.
There IS a bevelled slope on the exterior of the crystal Jue, maybe you can see it from this pic and the slope only exists on one side.
the man from whom I got the crystal jue has about more than 20 jade jue with one side slope as same as the jade one you show. I strongly guess they are from vietnam or some place near the boarder with china.
but we did find the same kind of jue in tombs of west Han period in south china.

I think my crystal one is from the same culture since they all has a bevelled slope on one side.
I can not explain if you said yours is quite sharply cut on the inside while mine seems to be more rough on the inside, maybe they were made in different places ? or times? or maybe both situations exist.

I will check the report later ...

R.M.