Many gemstones are cut ‘en cabochon’, that is, as an oval, rounded stone with a flat base, and a polished finish. The word ‘cabochon’ is derived from the Old Northern French for head which is ‘caboche’, which became cabbage in English.
The reasons for cutting stones as cabochons are generally three fold. The first reason is that a stone might be fragile and cannot stand up to being faceted. I often refer in my posts to the hardness of a stone, as ranked by Mohs scale of hardness. Stones that have a hardness under 7, such as quartz like amethysts and citrines, are often cut as cabochons because scratches are less apparent than if they were facetted. The second reason is that the stone may not be transparent and so is better set off as a cabochon. This would include stones like turquoise, jade, moonstones, and amber.
The third reason is if the stone is either asteriated, that is, shows an internal star like a star sapphire, is chatoyant, that is, shows an internal cat’s eye, or shows iridescence, like opals or labradorite.
One stone that is historically well known as being cut en cabochon is the garnet. The Latin word ‘carbunculu’ means ‘small, live coal. In Middle English, the word became ‘carbuncle‘. Originally, carbuncle was used to describe any red gemstone but over time, it became associated with deep red garnet cabochons.
Garnet cabochons were frequently foiled at the back to enhance their colour as the metallic foil used reflected more colour through the stone. The back of the stone was fully enclosed which can be a sign of foiling. Foiling was popular during the Georgian period but began to lose popularity during the Victorian period.
Photos: labradorite, garnet, opal, jade