Why is limestone light in color?

because all the materials it's made from are light colored. one of the ways limestone forms is when a creature dies buried in mud or other such stuff and when it decays the space is held by the dry dirt. water goes through and covers it with minerals. it's part of the fossil formation process. i don't know what exactally is in limestone but i think it's simliar to chalk. because you put limestone down to counter act acidic soil near plants.