From Minecraft Wiki
Rock may refer to several blocks:
Mossy), a block that appears to be made from rocks.
Stone, a block of solid rock.
Stone Bricks (
Variants), a block of stone with a brick pattern carved into it.
Gravel, an aggregate of fine stones.
Bedrock, an indestructible rock.
Polished), a variant of stone.
Polished), another variant of stone.
Polished), yet another variant of stone.
Variants), a sedimentary rock.
End Stone, a rock which makes up the End and strongly resembles sandstone.
Obsidian, a hard igneous rock.
Netherrack, a block, supposedly a rock type, found in the Nether.
Glowstone, a rock type which emits light.
Quartz, a metamorphic rock type which conducts redstone power in a way which can be utilised for devices like comparators.
Bricks), an underwater rock type.