This is a two-pound hammer; they also come in larger sizes. I call it a crack hammer, even though a real crack hammer is blunt on both faces, because it functions like one. It's suited for breaking outcrops and boulders of hard rock to collect large specimens, and also for driving a chisel or drill. The pointed cross-peen end will split thick-bedded rocks, so it's a decent all-in-one tool. If you do a lot of hammering rocks or work in metamorphic terrain, this can do things that the standard hammers can't. It weighs more than them and is useless for prying or grubbing. All rock hammers should be used wearing eye protection, because chips from rocks or from the hammer can fly in all directions.
I got the head of this hammer as a gift, discarded by another rockhound, and installed a new handle. It's made in Japan and is very solid. I have also made good use of it in demolition work around the yard.