Natural stones are widely used in building material since ages, both indoor and outdoor, to add performance and elegance to construction. Know all about these natural stones; their physical and chemical properties, color and textures, their uses in our life and availability in the world.

• Granite
• Limestone
• Marble
• Onyx
• Sandstone
• Slate
• Travertine

Granite, from igneous rock, is a very hard, crystalline, and primarily composed of feldspar, quartz accompanied by one or more dark minerals. It is visibly homogeneous in texture.Granite is the hardest building stone, and granite slabs and granite tiles occupy a prominent place among dimensional stones. Due to its hardness, resistance to weathering, capability to take mirror polish, fascinating colors and textural patterns, granite slabs and granite tiles are extremely popular.

Granite is the hardest building stone, and granite slabs and granite tiles occupy a prominent place among dimensional stones. Due to its hardness, resistance to weathering, capability to take mirror polish, fascinating colors and textural patterns, granite slabs and granite tiles are extremely popular.

Limestone is calcareous sedimentary rocks formed at the bottom of lakes and seas with the accumulation of shells, bones and other calcium rich goods. It is composed of calcite (CaCO3). The organic matter upon which it settles in lakes or seas, are preserved as fossils. Over thousands and millions of years, layer after layer is built up adding weight. The heat and pressure causes chemical reaction at the bottom and the sediments turn into solid stone, the limestone.

Limestone that will take a polish are considered marbles by most people, but technically, if there are still shells visible or the structure is not crystalline, it is still a limestone.

Marble, formed from limestone with heat and pressure over years in the earth's crust. These pressure or forces cause the limestone to change in texture and makeup. The process is called recrystallization. Fossilized materials in the limestone, along with its original carbonate minerals, recrystallize and form large, coarse grains of calcite.

Marble does not split easily into sheets of equal size and must be mined with care. The rock may shatter if explosives are used. Blocks of marble are mined with channeling machines, which cut grooves and holes in the rock. Miners outline a block of marble with rows of grooves and holes.

The name comes from the Greek word onyx which means nail of a finger or claw. Legend says that one day while Venus was sleeping Eros/Cupid cut her fingernails and left the clippings scattered on the ground. Because no part of a heavenly body can die, the gods turned them into stone which later became known as onyx.

Originally, almost all colors of chalcedony from white to dark brown and black were called onyx (SiO2 with impurities). Today when we think of onyx we often preface the word with black to distinguish it from other varieties of onyx that come in white, reddish brown, brown and banded.

The parent rock for quartzite is quartz-rich sandstone. As sandstone becomes deeply buried, rising temperature will fuse the quartz grains together forming the extremely hard and weather-resistant rock quartzite. Like marble, quartzite comes in many colors, but when pure it is light-colored. Quartzite tends to have a sugary appearance, and when broken the fractures cut through the sand grains, not around them as with a sandstone.

Chemically they are very resistant Mono-Mineralic rocks, principally of silica.They are highly resistant to avoids, alkalis and thermal impact. Insolubility in acids and alkalis is about 97%.

Sandstone is a sedimentary rock group which is mostly made up of tiny grains of quartz. Most sandstone is formed in oceans, lakes and rivers where tiny bits of rock and dirt settle to the bottom. Year after year, these layers of sand get buried under tons of more sand and dirt until it is turned into solid rock. Sandstone can be found in many colors.

The chemical constitution of sandstone is the same as that of sand, the rock is thus composed essentially of quartz. The natural cementing material that binds the sand together as rock is usually composed of silica, calcium carbonate, or iron oxide. Chemically sandstone is very resistant Mono-Mineralic rock, with silica as the principal.

Slates are dense and fine grained rock. The colour of slates are generally gray, red, brown and green ranging from dark to light. It is produced by the compression of clays, shale, and various other rocks developing a characteristic cleavage consisting sericite and quartz with biotite, chlorite, and hematite as principal accessories

Slates are or argillaceous origin of metamorphic rocks and can also be defined as a layered stone. Fossils may be sometimes preserved in slate but are invariably distorted. Folds are often apparent in the field. Too fine-grained are tough to distinguished with the naked eye.

Travertine is a white massive concretionary form of calcium carbonate, CaCO3 which is a resultant of deposition by springs (especially hot springs) or rivers. Travertine is usually hard and semicrystalline. It is often found in a beautifully coloured and banded as a result of the iron compounds presence or some other impurities.

Generally travertine is less coarse-grained and takes a higher polish than stalactite or stalagmite whose chemical composition and origin are similar.