What are the key differences in the geological characteristics between limestone and sandstone?

Limestone is a sedimentary rock formed from the accumulation of calcium carbonate, while sandstone is made up of sand-sized grains of minerals like quartz and feldspar. Limestone is typically softer and more porous than sandstone, which is harder and more resistant to weathering. Sandstone often has visible layers or bedding, while limestone can contain fossils and may exhibit a more uniform appearance.