Many years ago, this is what we did when we built a waterfall for my grandmothers Koi pond. We drove to the mountains and collected pieces off the side of the road where they had blasted through. We got many large pieces that were 100 lbs plus.
Canít do that anymore. All the rock is cleared and I often wonder if it all went to someones backyard or fish tank. Then again, even though the rock cause no problems for my grandmothers pond, I wonder if I would use any if there was any left. The thought of it sitting for 20 years in exhaust and oil would make me want to leave it.