| Limestone
is a sedimentary rock. 'Lime' is a general term
often used to describe limestone, quicklime, or
hydrated lime. 'Limestone' refers to the
naturally occurring calcium carbonate.
Limestone
is found in several areas of the world, Portuguese
limestone being one of the finest from which our
fireplaces are made.
Limestone
consists mainly of calcium carbonate (CaCO3)
and forms on the bed of the sea from the remains
of sea shells and other marine organisms. Fish,
shellfish, coral and marine micro-organisms
extract calcium and dissolved carbon dioxide from
seawater to make calcium carbonate. Their remains
settle on the sea bed where they may later be
buried by other sediments. Heat and pressure
causes these animal remains to form hard beds rich
in calcium carbonate. The remains of shells and
other fossils can often be seen in limestone.
If
limestone is very deeply buried, heat and pressure
will cause the calcium carbonate to recrystallize,
forming marble. Some of the finest marbles are
found in Italy which are used to make a range of
marble fireplaces.
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