The National Training Center for Stone & Masonry Trades Recieves Award of Excellence
ASHEVILLE, NC - The National Training Center for Stone & Masonry Trades(NTC) has been selected as one of the best educational resources on the Web by StudySphere.
StudySphere is one of the Internet's fastest growing sites of educational resources for students, teachers and parents. StudySphere has scoured the Internet to select only the finest sites to be included within its listing of educational links and has chosen NTC as one of the best.
"We are honored that NTC has received this award," says NTC Director Fred Hueston. "We have always strived to educate not only the dimensional stone industry but the consumer and general public as well."
Hueston is the former Publications Director for the
Marble Institute of America, a nationally syndicated newspaper columnist and Clear Channel radio talk show host who has consulted with both NASA and the White House.
For more information on NTC educational programs contact the National Training Center for Stone & Masonry Trades at
www.ntc-stone.com.
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 | | Marble | MARBLE: CHARACTERISTICS
This standard includes general information on the characteristics
and common uses of marble and identifies typical problems
associated with the material.
INTRODUCTION
Marble is an extremely hard, metamorphic stone composed of calcite
(CaCO3). It is formed as a result of the recrystallization of
limestone under the intense pressure and heat of geologic
processes. The effect of this process is the creation of a stone
with a very tight crystalline structure and small but definite
porosity. Because of its structure, marble can take a very high
polish and is a very popular decorative stone for architectural and
sculptural uses. The limited porosity of marble, especially
polished marble, makes it less vulnerable to the leaching effects
of water. Calcium carbonate, however, of which marble is composed,
is highly susceptible to attack by acidic agents. Marble is
readily dissolved by acids, even very dilute acids, however the
actual results of acidic exposure will vary with the nature of the
acid. Chlorides, nitrates, sulfates and other chemical compounds
react differently with marble and produce various by-products,
which have a wide range of solubility and impact on the durability
of marble. For this reason, it is always important to determine
the exact type of pollutants causing marble deterioration.
Marble itself can be of two types, one composed of calcite and the
other of dolomite. Dolomitic marble is much more resistant to acid
attack than calcite marble. The color of marble ranges from the
brilliant white of calcite to black, including blue-gray, red,
yellow and green, depending upon the mineral composition.
TYPICAL USES
Marble has many decorative and structural uses. It is used for
outdoor sculpture as well as for sculpture bases; in architecture
it is used in exterior walls and veneers, flooring, decorative
features, stairways and walkways. The way in which the stone is
used may be a factor in limiting or controlling the severity of
exposure. The use or function of the marble may also affect the
feasibility of applying certain treatments, but type of use is not
the primary factor in the major types of deterioration and damage
to which marble is susceptible. | |  |
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