Lava Rocks are made from a porus material that absorbs grease, which may lead to flare ups. Hot Rocks are consistent in shape, which allows the grease to run off. Hot Rocks should last longer than lava rocks and do not absorb grease. Coconut shell briquettes are made from 100% recyclable material, heat up quickly and give the authentic charcoal flavour to your food and are for single use only.