22nd Jan 2014
Faceted versus Cabochon stones
Ever wondered why so many sapphires are cut or faceted in oval shapes whereas many emeralds are faceted into square cuts? Basically it is because of the natural shape of the crystalline structure of the stone.
Faceting of a stone is typically planned so that there will be minimal waste from the rough and therefore maximum value and size to the finished cut of the stone. For example, a sapphire and a ruby (corundum crystals) are inherently oval and therefore most stones are oval cuts.
We find it interesting in some cases to source stones that are not the expected cut for the stone because they are more rare.
The cabochon stone is a smooth polish in a typically round or domed shape so it has no angles or facets on the face of the stone. Rose cuts have facets on top and are flat on the bottom.
This is a very pretty cabochon garnet bracelet. The ovals are all smooth.
Generally speaking cabochon precious stones (emeralds, rubies and diamonds) are less expensive than faceted stones. Some reports suggest that stones chosen to be polished have more inclusions and are better suited for the smooth look so that the focus is more on the intensity of the color saturation. The sugar loaf cabochon in precious stones can be very collective and equally breathtaking in appeal as a faceted stone in our opinion.
For sparkle however, faceting is de rigueur. There are many informational sources with regard to ideal cuts of faceted stones. Generally, speaking the stones needs to be cut to allow light to go into and out of the stone without any loss of light refraction. (See: Understanding the GIA Diamond Grading Report & Estimating a Cut Grade)
This aquamarine stone has pretty faceting that gives it a great sparkle.