Kinds of Natural Stones

Limestones

A limestone is nothing more than just calcium carbonate (CaCO₃). It start as floors of shallow tropical seas which is laid down since 150million years ago and is still being formed in parts of the tropics.

When Sea water, which contains carbon dioxide (CO₂), escapes warmed by the sun. the calcium and bicarbonate ions in the water combine to form calcium carbonate, just like scale forming in a kettle. This crystallises as calcite.

The famous ooliths (tiny spheres) in limestones are grains of sand or pieces of shell around which calcium carbonate which precipitated from the sea has stuck. The cement that sticks the ooliths together also consists of calcite crystals, which grew either on the sea floor or later in the rock when it was buried.

Shells of sea animals form grains in limestones, and some of them, such as pieces of starfish and sea lilies, promote the growth of cement crystals around themselves particularly well and result in limestones which are especially strong.

Over time, large crystals will grow at the expense of smaller crystals in any limestone, but especially if the stone is buried and warms up. And if it happens to be buried next to where granite is being forced up from deep in the earth near to the edge of a continental plate (when the granite will be at 800-900°C), the limestone will re-crystallise and become marble.

The Beauty of Natural Stones

Natural stones has been attracting human senses since the begining of human history.
It has been one of the most important part of human cultures for thousands of years.
Many ancient buildings still standing as great creations of old days with stones construction.
And today Its beauty shines million of houses and landmarks all over the world.


Natural Stones from Ancient World

THE STONEHENGE

Stonehenge is a prehistoric monument located in the EnglishWiltshire, about 8 miles (13 km) north of Salisbury. One of the most famous prehistoric sites in the world, Stonehenge is composed of earthworks surrounding a circular setting of large standing stones. Archaeologists believe the standing stones were erected around 2200 BC and the surrounding circular earth bank and ditch, which constitute the earliest phase of the monument, have been dated to about 3100 BC.


Lost City of Petra

Deep within the deserts of Jordan lies the ancient city of Petra. Through a narrow gorge it emerges into view, revealing awe-inspiring monuments cut into the surrounding cliffs.

Two thousand years ago, Petra people, The Nabataeans, carving the sandstone mountain became a wonderful city