Emerald

Emerald belongs to the beryl group. Its green colour arises mainly from traces of chromium and vanadium. It is precisely this combination that makes its formation geologically exceptional: beryllium and the colouring elements rarely come together in the same place in the Earth’s crust.

In emeralds, inclusions are part of the character of the stone. The typical inner appearance is often referred to in the trade as “jardin”, garden. Fine inclusions can provide clues to the formation and sometimes also to the origin of an emerald.

Colombia has been one of the most famous countries of origin for centuries. The mines of Muzo and Chivor in particular are known for intensely green emeralds. Other important deposits include Zambia, Brazil, Afghanistan and Ethiopia.

Gota de Aceite

A special and rare phenomenon in high-quality Colombian emeralds is “gota de aceite”, in English “drop of oil”. The finest growth structures within the crystal create a softly shimmering, slightly oily impression under the microscope. This effect is especially prized by connoisseurs.

Emeralds have a Mohs hardness of about 7.5 to 8, but fissures and inclusions can make them more brittle than their hardness would suggest. Many emeralds are therefore traditionally treated with oil to make surface-reaching fissures less visible. In particularly valuable stones, the degree of such treatment is an important quality criterion.

La Lechuga

One of the most extraordinary historical jewelled objects set with emeralds is the monstrance “La Lechuga” from the early 18th century. Created in Bogotá, the work is set with more than 1,400 emeralds and impressively demonstrates the significance Colombian emeralds have held for centuries.