Vincent Renault, gemologist and co-founder of Johya

Background

A gemology qualification is not a shop-window argument. It is what gives you the vocabulary, the instruments and the gestures to describe a stone without embellishing it — and, when necessary, to turn it down. An emerald is read under a 10× loupe, under the lamp, on the scales; it is not talked up.

Every stone in the catalogue has passed through Vincent's hands before arriving here: examination under the loupe and the UV lamp, weighing at each stage, photographs without retouching. Nothing is generated or "improved" by computer: what the listing shows is what the customer will receive.

What he checks on every stone

Color first. The emerald is a beryl that owes its green to chromium and vanadium. It is the criterion that weighs most heavily in value: its vividness, its saturation, and the way it holds up under different lights.

The "jardin" next. The inclusions of an emerald are not defects to be hidden: they are its fingerprints. A perfectly clean emerald should arouse suspicion rather than desire. What matters is not their absence, but their nature and their position.

Cut and weight last. A good cut serves the color and the soundness of the stone — the emerald is hard but fragile. Weight is never read on its own: two identical carats can be worth ten times less one than the other.

In the field, in Colombia

Purchases are made on site, in the emerald-bearing zone of Boyacá. The real work owes less to the folklore of the markets than to patience: see a great many stones, set aside the vast majority, come back, and buy only what can be defended once home.

This presence in the field makes it possible to document a stone's journey — photographs at purchase, during cutting, once cut — and to publish it. That is what Johya calls its traceability: not a promise, but a file that can be consulted stone by stone.

What he will never say

That a stone comes from a specific mine, without proof. Buying an emerald in Muzo does not prove it was extracted there: the place of purchase is not the deposit. Only an independent laboratory can attest an origin, and it attests a country — rarely a mine. When Johya writes "Colombia", that is what the certificate says.

That an emerald has had no treatment, for convenience. Nearly all the emeralds on the market are oiled: it is an old lapidary practice, accepted and exempt from the "treated" mention. Johya goes further and states the degree observed — none, minor, moderate. A stone containing resin, on the other hand, falls under a treatment that must be declared: it is flagged as such.

This line is not a commercial pose: it is the only way to stay accurate. What cannot be verified is not asserted.