Nature is a master baker. Deep inside the earth is her oven, heated thousands of years ago by great rising masses of molten rock. In this oven she baked, and with tremendous pressure turned limestone into hard marble.

In its purest form, marble is white. Different impurities often give it shades of pink, red, yellow, or brown, or form wavy lines or patches in it. Different colored crystals caught in the marble sparkle and flash in the sun’s rays. In some marble the remains of fossils add to its beauty.

Many other kinds of rock that take on a high polish and are used in building, such as granite, onyx, and porphyry, are often called marble. Real marble, however, is limestone that has been crystallized by nature’s process.

When marble is quarried a machine called a “channeler” cuts a series of channels or slots in the face of the rock. Some of these slots may be 2 to 3 meters deep and run from 18 to 24 meters long. Blasting cannot be used because it would damage or shatter the marble. The blocks are lifted out carefully by large derricks.

A great toothless saw is set to work on the rough stone, while a stream of water containing sand is kept running over it. The friction of the steel blade and the sand soon cuts the marble into the desired sizes. Sometimes a wire saw is used instead of a solid blade.

Pieces of marble are then placed on a circular rubbing bed and held stationary. Sand and water flow over the rotating bed surface, rubbing away the marble to an even level. Then still more grinding is done to give it a smooth surface.

The last fine polishing is done by a mixture of tin oxide and oxalic acid applied to the surface of the marble by means of a buffer wheel.