Emeralds are mineral beryls with a hexagonal crystal formation. Their green colour is due to traces of chromium and at times vanadium.

Much like a diamond, emeralds are graded by the four Cs, colour, cut, clarity and carat. Colour is by far the most significant criterion, but clarity is not far behind. For an emerald to be considered a top gem it needs a pure green hue as well as optical transparency.

Emeralds routinely have natural surface breaking fissures and inclusions, sometimes described as jardin, meaning garden, alluding to their natural mossy appearance.  A vast majority of emeralds are treated with fracture filling oil which enhances their clarity. Two emeralds that appear visually identical can differ quite substantially in their value depending on their treatment levels. Unlike a diamond, flawlessness in emeralds is judged by the eye and not a loupe. It is advisable to insist upon certified emeralds.

There are predominantly two countries producing large quantities of emeralds, Colombia being by far the world’s largest producer of emeralds, Zambia being the other.