Limestone
Limestone
is a type of rock made up mostly of calcite, a mineral form of
calcium carbonate. Most limestone is grey, but all colours of
limestone from white to black have been found.
All limestone are formed when the calcium carbonate crystallises
out of solution. It leaves the solution in many ways, and each
way produces a different kind of limestone.
Limestone can be formed almost completely without the aid of organisms.
This type of limestone is forced out of solution when the water
evaporates.
Evaporation of water in limestone caverns forms another variety
of limestone, called travertine, into stalactites and stalagmites.
Some limestone can be formed by the work of organisms. Many aquatic
organisms draw calcium carbonate out of the water and use it to
make their shells and bones. The oysters, clams, snails, corals,
and sea urchins do this. When the animals die the shells and bones
are broken up by waves into shell and coral sand and mud.
Limestone makes an excellent building stone because it can be
carved easily. Some factories use limestone to clean waste gases
and water before releasing them into the environment. Limestone
is also used to make lime and to smelt iron ore.
Limestone 1:
Limestone is typically formed over many years at the bottom of
oceans or lakes from the accumulation of shells, bones and other
calcium rich goods. If this limestone is subjected to intense
heat or pressure and a few millennium, a crystallization will
occur and the limestone will become a "true marble". Chemically
they are both still Calcium Carbonate (TUMS), but the marble will
have a crystalline structure and the limestone will have relatively
flat appearance.
Limestones that will take a polish are considered marbles by most
people, but technically, if there are still shells visible or
the structure is not crystalline, it is still a limestone.
Limestone that have magnesium in them are called"dolomitic limestones"
and are typically much harder and more resistant to weathering.
A typical characteristic of dolomitic limestones are their capability
of taking a flamefinish.
Limestones are typically used for flooring, wall cladding, vanity
tops, furniture, and often times ornate stonework.
