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GRANITE
What is Granite? The hardest among dimensional stones, this
natural igneous rock formation is used as a building material in the form of
granite tiles and slabs for flooring, wall cladding, roofing and a variety of
other interior and exterior applications.The word granite derives from the Latin granum, a grain, in reference to the
coarse-grained structure of this crystalline rock.
The geological definition of granite is "any plutonic rock in which the mineral
quartz makes up 10 to 50 per cent of the felsic components, and the ratio of
alkali to total feldspar is between 65 and 95 per cent." Commercially, any
holocrystalline quartz-bearing plutonic rock is generally included in the
granite group.
The granite group is one of the most versatile stone types available.
Granite, and granite-like materials, are capable of taking a wide variety of
finishes which allow the designer to custom-tailor the stone to the aesthetic or
performance requirements of a specific application.
Origin of granite
There are two theories for the origin of granite. The magmatic theory states
that granite is derived by the crystal fractionation of magma. Thus granite
bodies are the result of intrusion of liquid magma into the existing rocks. The
granitization theory states that granite is formed in place by extreme
metamorphism. There is evidence to support both theories, and both are useful to
explain different observed features. The two may actually merge: as metamorphic
conditions increase to the melting point of the metamorphosed granite, it will
melt and become a liquid magma.
MARBLE
What is Marble? Marble is metamorphosed limestone, composed of fairly pure calcite (a
crystalline form of calcium carbonate, CaCO3). It is extensively used for
sculpture, as an building material, and in many other applications.
Origins of 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.
SANDSTONE
Sandstone is a sedimentary stone that is typically the result of quartzite stone being eroded and redeposited by either wind or water. River beds, ocean beaches and sand dunes will all eventually become Sandstone. Sandstone is typically the youngest of the quartz based stones. Sandstones are typically used as flooring or paving materials. They are suitable for both interior and exterior applications.
Sedimentary stones that have high contents of quartz and silica are included in the commercial definition of "quartz-based" stones. Stone types such as sandstone, bluestone, and brownstone are included in this group. The quartz grains in such stones are cemented together by another material, commonly silica, iron oxide, or calcium carbonate. Like in sand, the variety of oxidized trace minerals in sandstone account for colors like tan, brown, yellow, red, gray and white.
LIMESTONE
Limestone is a sedimentary rockin the class known as sedimentary rocks. It is composed chiefly of calcite, CaCO3, and constitutes about 10 percent of all sedimentary rocks. Limestone may form inorganically or by biochemical processes. There are many types of limestone because of the variety of conditions under which it is produced.
SLATE
Slate is a fine-grained, homogeneous, metamorphic rock composed of clay or volcanic ash which has been metamorphosed in layers.
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