@dillyd @jlperuyero the one time I drilled a hole in a piece of seaglass I used a dremel (clone), a diamond tip, and worked under water, following some tutorial found online, and it worked quite nicely and easily
of course I was using a common shape of green glass, and not the good ones :D
I don't know whether those tutorials can still be found on 2026 internet :(
(edit: typo in dremel)