Here in AZ I was on a field trip awhile back looking for rhyolite (green lizard). I use mostly Eastwing hammers and a chisel, but for the life of me, that stone beat me as much as I beat it. I never saw such a hard stone, or was it my tools? I only have a 10" saw, so I am not looking to break up boulders, only pieces off of them. I tried my pry bar, everything. Got some shards when I slammed my cross peen sledge hammer / 12lbs into the stone. Other than that it was not a productive day. Up to now, splitting agate and jasper has worked for the most part. Onyx, calcite and other materials work well. I know they are much softer. Rhyolite must be 7+ on the MOHS. I did not see any cleavage evidence on the stone as well.
Anyone here use carbide tipped chisels when breaking off pieces? I know they are expensive, but most effective things are more $$ than Harbor Freight stuff. ]That is, are they worth the extra $$ ? I felt like I was in a prison chain gang along side a road, breaking stone, or trying too. I bench press 180, but this stone just whipped me. Gotta say it was a great work out though. Stayed very hydrated. In AZ, dehydration is the kiss!