Thanks for a great review Jade! As we can't tell how old sea glass is or what it is made up of sometimes we can get a real tough piece which blunts the drill bits quicker. Have a few of the
small diamond drill bits handy to use on these pieces of sea glass as these last a bit longer than the small diamond core drills because they have a larger surface area.
Plenty of cold water, very little pressure whilst drilling, and a slow speed will all also ensure the drill bits last as long as possible. I hope this helps.