A diamond can be cut and shaped only by another diamond. This is because diamond is the hardest substance known to man. Each diamond crystal can only be cut in certain directions, along which it is a little less hard. Even so, it takes hours to saw through a diamond. Diamonds can also be split, or ‘cleaved’, along four different directions through the crystal.
Nearly all diamonds are ‘brilliant cut’. This means that the facets — faces of gems — are cut at just the correct angles to make the most of a diamond’s sparkle. Each facet acts like a polished mirror inside the gem — it reflects the light and splits it into the colours of the rainbow.
There are several different stages involved in shaping a diamond crystal into a cut gem. Firstly, the crystals are sent to special factories and sawed with thin bronze discs coated in diamond dust and olive oil. The designer decides where each crystal is to be sawed.
Each diamond is then ‘bruted, or shaped. The bruter shapes the gem by holding another diamond against it while it is spun around at great speed. After grinding and smoothing the top facet, or ‘table’, the cutter carefully decides where to grind the first of the 16 main facets.
When the main facets are polished to the right size, the ‘brillianteer’ grinds the other 40 small facets. Over half of the original crystal has now been cut or ground away!
Picture Credit : Google