EMERALDOil-free emerald is the true rarity
Virtually every emerald on the market has been treated with oil or resin to reduce the visibility of surface-reaching fissures. The practice is centuries old and openly disclosed, but it means a stone certified with no clarity enhancement is genuinely uncommon. No-oil certification adds 50-100% over minor-oil pricing on comparable material, and a stone graded significant oil may be worth a third of its minor-oil twin.
Colombian material from Muzo and Chivor sets the reference for colour, a saturated bluish green that the Zambian and Brazilian deposits approach but rarely equal, and commands a 30–50% premium over them. In 2026 a top-tier no-oil Colombian stone at two carats exceeds $25,000 per carat, while commercial heavily-oiled material trades between $400 and $1,500.
Because emerald is an included stone by nature, buyers accustomed to diamond clarity standards misjudge it. The trade grades emerald on colour first. An untreated stone with fine colour and acceptable clarity is the material collectors and the trade rank highest.
SOURCE
Muzo & Chivor
The Colombian deposits that set the global colour reference, at a 30–50% premium.
TREATMENT
No oil accepted
Oiled and resin-filled stones trade in Stock Trade with the enhancement grade stated.
PREMIUM
50–100% over minor oil
A no-oil certificate roughly doubles the value of otherwise comparable material.
VAULT TRADE STANDARD
Only the finest emerald: vivid green, from 3 ct, no oil, with a top-four laboratory report and origin stated.
STOCK TRADEClarity enhancement, graded and declared
Emerald is treated more often than any other major gem, and the trade grades the degree openly: none, minor, moderate, or significant. What matters is not whether a stone has been oiled but whether the seller says so plainly and the laboratory agrees. Value falls as enhancement rises; a significant-oil stone may price at a third of its minor-oil twin.
Every listing states the enhancement grade from its report. Minor oil in a well-coloured Zambian stone is an ordinary, honest thing and prices accordingly. Undisclosed resin filling is the only version the trade considers deceptive, and it has no place here.
Colombian, Zambian and Brazilian material across a broad price range, suited to jewellery manufacture and everyday setting rather than long-term holding. For untreated emerald, see Vault Trade.