vaidurya

[Dan Lusthaus]

I'm wondering if someone on list can help me better identify a gem: vaiḍūrya
(vai.duurya or vaiDUrya). Monier-Williams gives only a "cat's-eye gem." The
Chinese corresponding term in Buddhist texts is not univocal -- sometimes
believed to be lapis lazuli, sometimes beryl, sometimes other things. Does
this term have a single referent in Sanskrit, or did it apply to different
gems at different times and places in India?

Thank you in advance.

Dan Lusthaus