Andean Scapes team · Updated
How a Colombian emerald is valued
There is no price per carat for “a Colombian emerald”. There are stones, and each one is valued for its color first, then its clarity, cut, size, treatment and origin. This is what professionals look at.
The short answer
Emeralds are valued above all for color, then for clarity and transparency, cut and carat weight.[1]
Quality for quality, the price of an emerald can rise dramatically as size increases.[1]
Color comes first
The most valued emeralds are bluish green to pure green with vivid saturation, a tone that is not too dark, high transparency and even color with no visible zoning.[1]
If the hue drifts too yellow or too blue, the stone is no longer emerald but another beryl, and its value drops accordingly.[1]
Clarity and the jardin
Eye-visible inclusions, the jardin, are expected in emeralds. Stones without them are rare and especially valuable.[1]
Inclusions only become a problem when they cloud transparency; then they reduce value dramatically.[1]
Cut, and emeralds in rings
Cutting decides how much color and weight survive. Almost all emeralds have fractures, and mistakes cost weight and value.[1]
Colombian rough is especially challenging: its color is more intense near the surface, so careless cutting can leave a stone much paler than the crystal it came from.[1]
For rings this matters. Emeralds are more brittle than corundum, and the emerald cut helps protect them because its vulnerable corners are faceted and give a safer place for prongs.[1]
Size
Quality for quality, price rises dramatically with size.[1]
Stones of 1 to 5 carats are popular as center stones; the smallest jewelry sizes run from 0.02 to 0.50 carat, and prestigious pieces can hold emeralds over 20 carats.[1]
Treatment
Fractures in emeralds are often filled with oils, waxes or artificial resins to improve apparent clarity. The type and amount of filler affect value.[2]
The amount of filler can range from insignificant to major, and its stability varies. Filled emeralds need care: no heat, chemicals, hot dishwater or sudden air-pressure changes.[2]
Laboratory reports
A GIA Emerald Report classifies clarity enhancement as minor, moderate or significant and includes an image of the stone; it describes the treatment, not a clarity grade.[1]
Origin opinions combine inclusions, spectroscopy and trace-element chemistry; a stone without diagnostic inclusions may get no origin opinion at all.[3]
Origin and the gota de aceite
Gota de aceite, “drop of oil”, is the trade’s name for high-quality Colombian emeralds.[4]
Origin has become an important factor in the price of fine emeralds, which is why laboratories invest in telling Colombian stones from others.[3]
Before you buy: what to ask
We do not sell emeralds and we do not quote prices: a figure without the stone in front of you means nothing. These are the questions professionals ask, whoever the seller is.
- Is the stone treated, with what, and how much?
- Is there a report from an independent gemological laboratory, and does its image match the stone?
- Does the report give an origin opinion, or does it say none was possible?
- How should this stone be cleaned and worn, given its treatment?
Frequently asked questions
- How much is a Colombian emerald worth?
- There is no single price. Value depends on color first, then clarity, cut and size, and price rises dramatically with size for the same quality.[1]
- What does gota de aceite mean?
- Spanish for “drop of oil”, it is the trade’s term for high-quality Colombian emeralds.[4]
- How do I know an emerald is Colombian?
- Only a gemological laboratory can give an origin opinion, using inclusions, spectroscopy and trace elements.[3]
Sources
- GIA Gem Encyclopedia. Emerald Quality Factors. Gemological Institute of America.
- Weldon, R. An Introduction to Gem Treatments. GIA Gem Encyclopedia.
- Saeseaw, S., Renfro, N. D., Palke, A. C., Sun, Z. et al. (2019). Geographic Origin Determination of Emerald. Gems & Gemology, 55(4). GIA.
- Weldon, R., Ortiz, J. G. & Ottaway, T. (2016). In Rainier’s Footsteps: Journey to the Chivor Emerald Mine. Gems & Gemology, 52(2). GIA.