Marble
For glass, metal, or ceramic toys, see marbles.Marble is a
metamorphic rock resulting from the
metamorphism of
limestone, composed mostly of
calcite (a crystalline form of
calcium carbonate,
CaCO3). It is extensively used for
sculpture, as a
building material, and in many other applications. The word 'marble' is colloquially used to refer to many other stones that are capable of taking a high polish.
Faux marble or
faux marbling is a wall painting technique that imitates the color patterns of real marble (not to be confused with
paper marbling). Marble dust can be combined with cement or synthetic resins to make
reconstituted or
cultured marble.
Places named after the stone include
Marble Hill, Manhattan, New York; the
Sea of Marmara;
India's
Marble Rocks; and the towns of
Marble, Minnesota;
Marble, Colorado; and
Marble Arch,
London. The
Elgin Marbles are marble sculptures from the
Parthenon that are on display in the
British Museum. They were brought to
Britain by the
Earl of Elgin.
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Marble. |
Marble is a
metamorphic rock resulting from regional or at times contact
metamorphism of
sedimentary carbonate rocks, either
limestone or
dolostone. This metamorphic process causes a complete recrystallization of the original rock into an interlocking mosaic of
calcite and/or
dolomite crystals. The temperatures and pressures necessary to form marble usually destroy any
fossils and sedimentary textures present in the original rock.
Pure white marble is the result of metamorphism of very pure limestones. The characteristic swirls and veins of many colored marble varieties are usually due to various mineral impurities such as
clay,
silt,
sand,
iron oxides, or
chert which were originally present as grains or layers in the limestone. Green coloration is often due to
serpentine resulting from originally high magnesium limestone or dolostone with silica impurities. These various impurities have been mobilized and recrystallized by the intense pressure and heat of the
metamorphism.
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Natural patterns on the polished surface of "landscape marble" can resemble a city skyline or even trees (see photo). |
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Blocks of cut marble at the historic mill in Marble, Colorado |
Some historically important kinds of marble, named after the locations of their
quarries, include:
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Paros from
Greece*
Penteli from
Greece*
Carrara from
Italy*
Proconnesus from
Turkey*
Macael from
Spain*
Makrana from
India*
Danby from
Vermont*
Yule from
ColoradoWhite marbles, like Carrara, have been prized for
sculpture since classical times. This preference has to do with the softness and relative
isotropy and homogeneity, and a relative resistance to shattering. Also, the low index of refraction of
calcite allows light to penetrate several millimeters into the stone before being scattered out, resulting in the characteristic "waxy" look which gives "life" to marble sculptures of the human body.
In the
construction trade, the term "marble" is used for any massive, crystalline calcitic rock (and some non-calcitic rocks) useful as building stone. For example,
Tennessee Marble is really a massive, highly fossiliferous gray to pink to maroon
Ordovician dolostone, known as the
Holston Formation by
geologists.
Colorless marbles are a very pure source of
calcium carbonate, which is used in a wide variety of industries. Finely ground marble powder is a component in
paints,
toothpaste, and
plastics;
calcium carbonate can also be reduced under high heat to
calcium oxide (also known as "lime"), which has many applications including being a primary component of most cements.
The word "marble" derives from the
Greek marmaros, "shining stone" (
OED). This stem is also the basis for the English word "marmoreal" meaning "marble-like".
As the favorite medium for
Greek and
Roman sculptors and architects, marble has become a cultural
symbol of tradition and refined taste. Its extremely varied and colorful patterns make it a favorite decorative material, and are often imitated — e.g. in background patterns for
computer displays.
In folklore, marble is associated with the astrological sign of
Gemini. Pure white marble is an emblem of purity. It is also an emblem of immortality, and an ensurer of success in education.
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Three marble patterns available in a graphics program (the GIMP). |
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list of minerals*
building material*
limestone*
travertine*
alabaster*
granite*
sandstone*
marble sculpture*
marquetry — inlaying with marble and other stones.
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faux marbling — painting surfaces to look like marble.
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scagliola — imitating marble with plasterwork.
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cultured marble — marble powder with a binder.
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paper marbling*
Stones of India Marble
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Tips for cleaning marble *
Calcite, Limestone and Marble by Kelly Snyder and Peter Russel
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How to engrave marble with laser.*
Marble Institute of America, a trade organization.
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Learning to carve by Marc Levoy.
