[quote=mike31154;425251]Yoiks, a masonry bit should take care of most any rock like material! Have you tried or do you have access to, dare I say it, a hammer drill to use with the masonry bit? The hammering action can make quite a difference, although it might just shatter the rock too. I know some of my pieces are rather fragile and I've broken several just rearranging them in the tank. The stuff you're dealing with sounds bulletproof though.
I found if you use a hammer drill, start with a small hole and work your way up through the bit sizes until you get to the hole size you want. Less likely to shatter the rock this way.
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225g reef
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