|
What is Marble,
Limestone, Travertine, Slate & Granite?
Marble
Marble is the geological name for
massive, compact limestone which has been completely
re-crystallized by heat and pressure, capturing many foreign
substances, thus creating a unique variety of colors and veining
(minerals). Marble is simply changed limestone, or to be more
specific, metamorphic limestone. The veining which is caused by
dissimilarity of materials, often represents areas of weakness
within many marbles. Like numerous other stones such as
Calcareous stones, travertine and onyx, Marble is also composed
chiefly of calcium carbonate.
Marble can be polished and used for architectural and ornamental
purposes. Its color varies from white to black, being sometimes
yellow, red, and green. Marble is sometimes beautifully veined
or clouded. It is preferred for floorings and accentuates the
living sphere with its sheer opulence.
Marble stone is relatively softer than other stones and offers
less stain resistance. Thus it requires careful maintenance and
should be treated as fine furniture. Marble is susceptible to
damage from citric acids, alcohols and oils. Spills should be
wiped up immediately. Treated properly, marble will remain
elegant for decades.
Limestone
Limestone is formed as a result of millions of years of sea
shells and bones of sea creatures settling as sediment on an
ocean floor (hence it is called a sedimentary stone). The
calcium in the bones & shells combines with Carbon Dioxide in
the water to form Calcium Carbonate, which is the basic mineral
structure of all limestone and marble. Less than 3% of the stone
is the color, which is simply other natural elements present
when the stone formed (ie iron deposits give you a reddy brown).
Limestone is available as plain rock. Since it is not
crystallized, it cannot be polished.
It is available in elegant shades of yellow, blue, brown and
black. Due to its durability and longlife, limestone is
generally used as building stone and for making statues. Its use
as wall cladding material has also gained immense popularity.
Travertine
Travertine also began as limestone, which over time, through
geological shifting, found its way deep in the Earth. The porous
nature of limestone makes it a great reservoir for liquids.
Aquifers, which are the enormous underground pools of water that
feed our wells and water our cities, are the remnants of ice age
melting, which sank below and was absorbed by limestone. Heated
by the Earth's inner core, the water rises as steam and hot
pressurized water, to form hot mud baths, "Old Faithful", "
Mammoth Springs", and other gizers. This rising hot water,
dissolves the limestone and brings with it granules from below,
forming mud beds on the surface. If enough time transpires, and
the mud beds cool, they will crystallize into solid stone called
travertine.
Slate
Slate is metamorphic rock, like the marble. However, instead
of forming from a pre-existing limestone (like marble), slate is
formed from the low-grade metamorphism of the sedimentary rock
shale and volcanic ash deposited on sea floors. Slate, like
shale ("mudstone"), is a very fined-grained rock of mostly
microscopic clay minerals with some microscopic quartz and
calcite. Slate can also contain some of the same minerals found
in granite, which make some slates iridescent and/or hard. The
alteration of shale by heat and pressure produces the pronounced
partings (slaty cleavage) that give slate its characteristics.
Like limestone and marble, the color comes from trace metals.
The wild colors on most Chinese and Indian slates are the result
of splitting the slate along natural layers, which exposes the
metals to the atmosphere, and they oxidize (rust).
Granite
Granite is an igneous rock, which, during its development,
remains in the form of liquid magma in the center of the Earth.
Unlike lava, granite did not come to the surface. It remained
trapped inside the earth where it slowly cooled and
crystallized. Due to the extreme pressure within the Earth, and
the absence of atmosphere, granite is formed very dense with no
pores. Granite is infact a host of ingredients, including common
minerals like feldspar, quartz and mica, and the proportions
vary considerably from deposit to deposit. The major mineral
component of granite is feldspar. Quartz, which is the hardest
part of Granite (it ranges from 70% to 80% the density of a
diamond) comprises only between 10-30% of the rock, whereas
feldspar (potassium and sodium varieties) makes up 60-80%. (This
contrasts dramatically with GRANIREX, which is 93% natural
Quartz).
Granite comes in various colors varying from stark white to
beiges, browns, reds, pinks, yellows, greens, blues, grays and
blacks. Textures range from clear to coarse and crystalline to
heavily veined. These natural materials were created in the
earth many years ago by processes and conditions, which gave
each of them varying properties and characteristics.
Granite is the most durable of the stone surfaces, which makes
it the best choice for a worry-free countertop. It is extremely
durable, stain resistant and easy to care for. It is chip
resistant and is unlikely to crack or scratch during normal use.
|
