See also: Troll
Stone trolls live in mountains and other rocky region. Their stomach acid is strong enough for them to easily eat rocks and stones, which allows them to survive in very inhospitable land since they have little to no competition for their food source.
Their bodies tend to be stony and solid - as the saying go, "You are what you eat". Due to their morphology being half stone and half flesh, Stone Trolls are extremely resilient to magical effects. There rocky diet allows them to survive in these harsh land's were other creature's find it almost impossible to live due to the lack of resources in the area.
Their skin is dry and tough as the rocky mountain's they inhabit. They use crude weapon's fashioned of stone and wood and lob boulders.