Diamond is an exceptionally hard form of carbon. Colourless diamonds are the most popular but they occur in a wide range of colours, mostly pastel but red, blue and even black diamonds do exist. Pink, light green and lavender diamonds are rare; deep pink diamonds are particularly rare.
It was believed that possessing a diamond would give courage and strength and drive away the spirits of the night. To achieve this, however, the diamond had to found; if it was bought, it would lose its powers. However, if it was offered as a pledge of love the diamonds powers could return – hence its use in engagement rings.
The Hindus classified diamonds into four types.
- colourless “brahmin” diamonds brought power, friends and riches;.
- brown or champagne coloured “kshatriya” diamonds brought success;
- blue “svaisya” diamonds brought good luck and
- red or yellow diamonds brought all types of good fortune but were for the exclusive possession of kings.
Until about 1800, it was customary for diamonds to be set with the back fully enclosed. This eliminated any light coming through the stone and subdued its brilliance. About this time it was discovered that the diamond was shown to its best advantage if the back was left open. Throughout most of the 19th century, the preferred diamond setting was the cut-down collet. In this, the stone is set in a short tube which is chamfered away at the top leaving little claws to hold the stone in place. Diamonds were set in a laminate of gold and silver. Silver was at the front to accentuate the whiteness of the diamond; gold was at the back to avoid marking the skin or clothing.
The discovery of the great diamond resources of South Africa in 1859 changed the way in which diamonds were set and cut. Before this time, the emphasis was on making the diamond appear as large as possible and on not wasting any material in the cutting. From the 1860s, with the availability of larger and less expensive diamonds, openwork settings which let in as much light as possible in order to show off the brilliance of the stone were used. From 1872, the “brilliant” method of cutting diamonds replace the older “rose” cut. The natural shape of a diamond crystal is a tetrahedron but the best optical properties are obtained by cutting the crystal to be almost round and much shallower. Achieving this means wasting almost half of the mass of the diamond. (One attempt to make use of the resultant diamond dust was selling it for sprinkling on the hair. The fashion did not last.)
From about 1900, the gold and silver laminate settings which had been used for diamonds were superseded by white gold or platinum settings.