EMERALDS

The most prized emeralds have historically come from Colombia (the Muzo, Chivor and Coscuez mines), celebrated for their pure green with a slight blue undertone. Zambia has become the world's second major source since the 1980s, producing emeralds with a richer, more saturated green and excellent value for money. Brazil, Ethiopia and Afghanistan also yield remarkable stones. At Bonnot Paris, we source exclusively from Colombia and Zambia through our Jaipur office.

The price of an emerald depends on four criteria: colour (the intensity of green takes precedence above all), clarity, cut and origin. As a guide, expect €1,500 to €4,000 per carat for a good-quality Zambian emerald (1 to 2 carats), and €3,000 to €10,000 per carat for a Colombian emerald of equivalent quality. Exceptional, untreated stones can reach several tens of thousands of euros per carat.

Inclusions are an almost universal characteristic of the emerald — so much so that they are known as its “garden” (jardín in Spanish). They result from the particular geological conditions under which the stone forms. Unlike sapphire or ruby, an emerald entirely free of inclusions is extremely rare and even suspicious — it is often the hallmark of a synthetic stone. Inclusions are the signature and the proof of authenticity of a natural emerald.

More than 99% of emeralds on the market are oiled: cedar oil (or a colourless resin) is introduced into natural fissures to improve visual transparency. This treatment is internationally recognised and accepted, and does not alter the stone. An untreated emerald (noted as “no oil” on the certificate) is extremely rare and commands a price two to five times higher for equivalent quality. For a classic jewellery setting, oiling is the standard; for a heritage investment, an untreated stone is preferable.

Both offer a range of greens, but their characteristics differ considerably. The emerald has a more intense, deeper green, often with a slight blue cast; the green sapphire is softer in tone, cleaner, and typically inclusion-free. In terms of durability, the green sapphire has a clear advantage (hardness 9 versus 7.5–8 for the emerald) and requires no protective setting. For carefree everyday wear, the green sapphire is the wiser choice; for chromatic depth and long-term value, the emerald remains unrivalled.

Yes, provided two rules are observed. First, choose a protective setting (bezel, halo, or high-claw prongs) that shields the stone from lateral impacts — a critical point, as the emerald is more delicate than sapphire or diamond. Second, remove the ring for sport, housework involving chemicals, or any high-risk activity. At Bonnot Paris, settings are always designed with everyday wear in mind.

The rectangular emerald cut with cropped corners is the most iconic: it was conceived specifically for this stone, reducing pressure on the corners and minimising the risk of fracture. The cushion cut is equally well suited and remains a classic choice. The oval cut is particularly effective at showcasing the depth of colour. Avoid cuts with sharp, angular points (marquise, pear) which leave the stone exposed to impact.

Clean your emerald with a soft, lightly dampened cloth — never with an ultrasonic cleaner or steam, as these methods risk removing the treatment oil and revealing inclusions. Avoid all contact with chemicals (perfume, creams, soap, chlorinated water). Every three to five years, it is advisable to have the emerald re-oiled by a specialist to preserve its transparency. Bonnot Paris offers this service for the lifetime of every creation.