text: why have sandstone, and limestone been used as building materials for thousands of years?   both materials are natural sedimentary rocks. as hardened ancient sediments that become hard resulting from time and burial.  both limestone and sandstone tend to break into flat layers that can be further broken into squared-off chuncks.  that squared-off shape serves well for construction. try building a wall with round stones.  both sandstone and limestone also  last well in the face of the elements of weather.   sandstone is a little better at lasting against the weather than limestone, but limestone is a little easier to work with for the stone worker, since the mineral calcite which it is composed of, is softer.  students can go to look at dated burial stones with their dates to learn how these to material stand up to the weather.   they will see that dates on monuments made of limestone and marble (composed of the same mineral) tend to become more faint with time than dates on  sandstone monuments.  even so both sandstone and limestone monuments last hundreds of years. in dry climates such as egypt limestone building stone such as in the pyramids lasts nearly as well as sandstone.   in brief sandstone and limestone are abundant natural materials that are long-lasting and can be easily formed into a useful squared-off shape.