Hi, I have a question regarding building a multi-rock bubbler water feature and bird bath. What's the best technique to carve out a rock bowl after drilling a 1" hole thru the middle? I've seen natural rock carved basin, bowls, and bird baths/feeders at a local rock yard but the rock seemed fairly light and dense almost like lava rock...looked like limestone but weight was much less. I would like to see what rock others are using with good success. I can drill straight thru natural limestone without a problem but really haven't tried any type of carving to create a shallow basin and also creating the rock pedastol. I asked the counter person and the said the rock comes out of Mexico where they carve them out. Any info will be greatly appreciated. Thanks!