subject: Primary Kinds Of Stone Used In Building [print this page] Limestone is a sedimentary rock consisting primarily of lime which was formed by a variety of biological, chemical and physical processes that took place over millions of years. Generally most limestone is chiefly composed of calcium carbonate, the organic remains of shells and coral.
Dolomitic limestones are chemically magnesium carbonate. The fossils and other sedimentary structures which limestone contains provides a key as to the environment in which limestones where formed.
Limestone used outside must be protected from water and frost damage. If the porosity of the stone is to high, water may collect in the stone, freeze, and then swell. This may cause the stone to flake, crack or to split.
Limestone is also used to make lime cement. This process involves burning the limestone in kilms to produce the lime cement. And this lime cement when mixed with sand and water would be used to cement the building stones or fired clay bricks together to form walls and other parts of the castle. This process of making and using lime cement will be discused in detail later.
Sandstone is a sedimentary rock consisting primarily of quartz, occasionally felspar and other sand particles, and small rock particles all cemented together into a firm stone. These materials eroded from older rocks were sorted and deposited by rain and wind to form beds of layered materials. The sandstone was then formed by a chemical and physical process similar to the formation of limestone. The various minerals, such as iron oxides and carbonates, that leached into the layered sand beds gives sandstone its rich and varied colors.
Slate is a metamorphic rock. This means that this fine grained rock is the result of the actions of pressure, heat and water upon clay and silt sediments deposited on ancient sea beds over millions of years ago. Mountain building forces subsequently gradually folded, crumpled and compressed these deposits into the shale. This has resulted in a very compact and highly crystalline rock structure.
