The soft limestone stones are ideal for today's more casual and comfortable environments. Generally these soft beiges and tans are suitable for bathrooms, fireplaces, counters and floors. Limestone is a sedimentary rock that is formed at the bottom of lakes and seas, as organic matters settle to the bottom. As more and more layers build up over thousands and millions of years, adding more and more weight, the heat and pressure cause chemical reactions to take place to harden the sediments into solid stone.