In order to make a sparkling stone from a rough diamond, processing is necessary. This must be done very carefully because if mistakes are made, the stone can disintegrate into small fragments or even burn up.
The most important steps of the processing are: cleaving or sawing, bruting and polishing. Because diamonds are composed of layers, they can be split (cleaved). When faceting the diamond, one must take account of the ‘grain’, the direction in which the crystals have grown.
In Venice, at the beginning of the 14th century, diamonds were cut for the first time. In the 17th century, Amsterdam became the world center for the processing of, and trade in, diamonds. Today, the main polishing centers are: Antwerp, Mumbay, Surat, Guangzhou, Tel Aviv and New York.