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Old Mine Colombian Emeralds

An old mine Colombian emerald is a trade description for an emerald showing the finest saturated, slightly bluish green with a soft glow, the colour associated with historic production from Muzo. It is not a laboratory grade and no report issues it as one; it is a dealer's judgement of colour, applied to a small fraction of Colombian stones. Byrex Gems offers old mine quality Colombian emeralds to the jewellery trade from Toronto, filmed unedited, with prices for approved buyers and viewings by appointment.

Where to buy old mine Colombian emeralds in Toronto

Byrex Gems lists 29 old mine Colombian emeralds online today. 29 of them come with a report from laboratories including GRS. Viewings are at our Toronto office, 27 Queen Street East, Suite 407, steps from Queen subway station, by appointment. We have supplied coloured gemstones and natural fancy colour diamonds to jewellers and designers since 1988, and welcome private clients by appointment. Prices are shown to approved trade accounts; private clients can ask us on WhatsApp, where we reply within 12 hours, or by email within 24 hours. Every stone ships insured, worldwide.

What does "old mine" mean for a Colombian emerald?

In the emerald trade, "old mine" describes a colour rather than a date or a place. The term grew out of the reputation of stones that came from Muzo in earlier centuries, when the finest crystals showed a deep, saturated green with a hint of blue and an inner glow that seemed to come from within the stone. Dealers began to call any emerald with that colour "old mine", and the usage stuck.

The colour is a slightly bluish green of medium to medium-dark tone, strongly saturated, even across the stone, with high transparency and the soft, velvety light return typical of Colombian material. It is the look collectors picture when they imagine a Colombian emerald, and it is rarer than the general run of Colombian production, much of which is lighter, more yellowish or more heavily included.

Because it is a description of colour, an old mine stone can in principle come from Muzo, Chivor, Coscuez or elsewhere in the Colombian belts. Chivor stones with a cool bluish green are sometimes described this way too. What matters is that the stone shows the colour, not that anyone can prove which shaft it came from.

How laboratories treat the term old mine

No major laboratory grades an emerald as old mine. GIA, Gübelin, SSEF, AGL and CDC state the species and variety, an origin opinion, and the degree of clarity enhancement; they do not rank colour against a historic standard. Where the term appears on a document at all, it is in a comment, an appendix or a letter describing the stone's appearance, and it should be read as an observation rather than a grade.

What the report does establish is the foundation under the claim. Origin is an opinion based on inclusions, spectra and trace-element chemistry, and the report must say Colombia for the description to hold. The enhancement grade carries the rest of the weight. GIA describes clarity enhancement as none, minor, moderate or significant. SSEF and Gübelin use a comparable ladder that also includes insignificant. AGL grades on its own scale from faint to prominent.

In practice, buyers expect an old mine stone to carry a grade of none, insignificant or minor, usually with a traditional oil rather than a resin. A stone with the right colour but a moderate or significant grade is still Colombian and still beautiful, but the trade would hesitate to call it old mine quality.

What to check before buying an old mine emerald

Begin by confirming the colour with your own eyes under daylight-equivalent light, viewed from the top, and then under a warmer lamp. The stone should hold a saturated, slightly bluish green in both, with no shift toward yellow and no grey. Look across the whole face for evenness; the best stones show the colour everywhere rather than in a single strong patch.

Read the report next. Check that the origin opinion is Colombia and that the enhancement grade is none, insignificant or minor in the laboratory's own terms. Ask whether the filler is oil or resin. If the stone has an older report, consider whether a current one is needed, because enhancement can change if a stone has been re-oiled since it was last examined.

Most old mine quality stones are emerald cuts or elongated cushions, following the long Colombian crystal. Inspect the corners and the girdle for surface-reaching fissures, and let the setter know where they are. Sizes above a few carats in this colour are scarce, so a close match for a pair is more realistic than a true pair; Byrex describes two stones as a pair only when the parcel paper or report does, and otherwise as a close match. Specify a protective setting and no ultrasonic cleaning.

What drives the value of old mine quality

The premium for old mine quality rests on colour, and the colour is rare. Saturation and tone must both sit in a narrow band: strong enough to glow, not so dark that the stone loses light. The slight bluish component separates this look from the warmer, more yellowish green of much Colombian production, and buyers pay for that distinction.

The enhancement grade is the second pillar. The description is usually reserved for stones graded none, insignificant or minor, so a lower grade undercuts the claim and the price. Transparency comes next; an old mine stone should look clean and alive even when a modest jardin is present under magnification.

Size multiplies all of this, because clean, saturated Colombian rough large enough for a stone of several carats is seldom found. A report from a laboratory the auction houses accept, such as Gübelin, SSEF, GIA or AGL, adds confidence. Provenance, where it can be documented, adds a final layer, which is why stones from old collections and estate pieces are sought after when they are recut or resold.

Old mine emeralds in history and at auction

The stones that gave the term its meaning reached Europe and the East in the centuries after the Spanish conquest of Colombia. Muzo was worked intensively, and its finest crystals were traded to the Mughal courts of India, to Persia and to the treasuries of Europe. Engraved Mughal emeralds, the emeralds in the Iranian crown jewels and those in Spanish church treasures are, for the most part, Colombian stones of this period, and many show the saturated bluish green that dealers still describe as old mine.

At auction, the description surfaces in catalogue notes for important Colombian emeralds, usually alongside a laboratory report stating Colombian origin and a low enhancement grade. The Rockefeller Emerald, sold at Christie's in New York in 2017, is often cited as a modern reference for the look.

For the trade, the practical point is that old mine is a claim to be tested, not a label to be accepted. Byrex applies it sparingly, only where the colour is genuinely of that standard and the report supports it.

Buying Old Mine Colombian emeralds from Byrex Gems

Since 1988, Byrex Gems has supplied Old Mine Colombian emeralds to the jewellery trade from Toronto. The confidence of more than seven thousand trade customers has been earned one stone at a time. Many of our Old Mine Colombian emeralds come with reports from GRS, SSEF, Gübelin, GIA and other leading laboratories, and each stone is filmed in our office, exactly as it is.

Approved trade buyers see prices online. Everyone else is welcome to write: WhatsApp +1 (437) 450-3786 brings a reply within hours, and an email to info@byrex.com an answer the same day, seven days a week. What is listed is a part of what we hold: more Old Mine emeralds are kept in the vault, and what we do not hold ourselves we can source through our offices worldwide. We receive clients by appointment in Toronto, Hong Kong, Bangkok and Dubai.

Old Mine Colombian Emeralds: questions buyers ask

Where can I buy old mine Colombian emeralds in Toronto?

Is old mine a laboratory grade for emeralds?

No. It is a trade description of colour, the saturated, slightly bluish green associated with historic Muzo production. Laboratories state origin and the degree of clarity enhancement; if old mine appears on a document, it is as a comment or appendix, not a grade.

Does old mine mean the emerald was mined long ago?

Not necessarily. The term refers to the colour that early Muzo production was famous for, and it is applied to any Colombian emerald showing that colour today. Age and provenance are separate questions that a report does not answer.

What enhancement grade should an old mine emerald have?

Buyers expect none, insignificant or minor in the issuing laboratory's wording: GIA uses none, minor, moderate or significant; SSEF and Gübelin also use insignificant; AGL grades from faint to prominent. A moderate or significant grade weakens the claim.

Which reports accompany Byrex old mine emeralds?

Reports from Gübelin, SSEF, GIA, AGL, GRS or CDC, depending on the stone. The report states Colombian origin and the enhancement grade; Byrex adds the old mine description only when the colour meets that standard in person.

Can an old mine emerald be a Chivor stone?

Yes. The term describes colour, not a mine, and reports name only the country. Some Chivor stones show the cool, saturated bluish green the term implies, though Muzo gave the description its name.

Does Byrex source old mine emeralds for a specific commission?

Yes. Byrex searches through its offices and partners for stones that are not in the collection. State the size, shape, enhancement grade and the colour you need, ideally with a reference stone or image, and Byrex will present candidates with their reports.

How is old mine colour different from ordinary Colombian green?

Ordinary Colombian production ranges from light and yellowish to dark and included. Old mine colour is saturated, slightly bluish, of medium to medium-dark tone, even across the stone and transparent, with a soft inner glow. Only a small fraction of Colombian stones reach it.

Can I compare old mine emeralds in person in Toronto?

Yes. Viewings are by appointment at 27 Queen Street East, Suite 407, Toronto. Byrex places stones side by side under daylight-equivalent and warmer light so the difference in colour and glow is visible, with each report on the table.

Byrex Gems, 27 Queen Street East, Suite 407, Toronto. Coloured gemstones and natural fancy colour diamonds for the trade since 1988, and for private clients by appointment.

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