A Guide to Gem Cutting

If you've ever wondered why two stones of the same type can look completely different, the answer is usually in the cut. The way a gemstone is shaped and finished determines how it catches light, how it wears, and ultimately how much you want it. Here's what you need to know.

Lapidary is the art of cutting and working with gemstones. There are four main styles.

TUMBLING
The most basic form. Rough stones go into a revolving barrel with progressively finer abrasives until a polish is achieved. Think of it as a highly controlled version of what rivers and oceans do to pebbles over centuries, just faster and with a much better finish. 

CABBING - CABOCHON CUTTING 
The most common cut in jewellery. A cab has a flat bottom and a smooth domed top, no facets. Opals, turquoise, and moonstone are classic examples. The beauty here is in the material itself, its colour, pattern, and translucency, not in geometric light play.

FACETING
This is where the engineering comes in. Faceting covers a stone's surface in precisely arranged flat surfaces, each one calculated to reflect light back through the stone. That's brilliance. The rainbow flashes you see in diamonds are something different, called dispersion or fire, and the two are often confused.

CARVING

The most demanding of the four. Carving requires both technical lapidary skill and genuine artistic vision. Cameos are the most recognisable example, typically cut from shell or agate. Designs cut into the surface are called intaglios; designs carved on the back, reverse intaglios. Some carved stones are never set into jewellery at all. They're made simply to be looked at.

Understanding how a stone is cut changes how you look at jewellery. It's the difference between buying something because it's pretty and knowing exactly why it's beautiful.

Written by Anaita Thakkar for Lustre Jewellery