FMF - Friends of Minerals Forum, discussion and message board

[Fiebre Verde]

Emerald clusters are fairly common in the Western belt.
Complex crystallization patterns can be clearly seen on the faces of the various prisms (first 2 images).
Last image features a couple of clear colorless quartz crystals intersecting the upper part of the cluster.

[Fiebre Verde]

This specimen comes from the Buena Vista mine in the Chivor district.
The Buena Vista mine is located on a hill overlooking the surrounding area (might explain the origin of the name "Nice view"?).
Administratively speaking, it is off the "green" state of Boyacá by a few hundred meters, where virtually all the Colombian emeralds come from.
Not only the view from that open-pit mine is nice but also the quality of the emeralds it produces (when the mine operates, which does not happen often).
The one featured here below is a fine example of the top quality material produced in the Chivor district, from a collector's point of view.
Host rock is a hard clay material also known as argillite.

[Tobi]

The more emeralds you show us, the more fascinated I am!

[Fiebre Verde]

[Fiebre Verde]

A small specimen from a new find in the Chivor district.
All the crystals I have seen from this find exhibit a strong saturation.
Host rock is a crumbly gray shale.

[Fiebre Verde]

A cluster from the Cunas mine which has been continuously producing fine emeralds in the past few years.
The Cunas mine was privately owned by the emerald czar Victor Carranza.

[Fiebre Verde]

The beryls are associated with black and white calcite. No host rock.

[Fiebre Verde]

Aggregate of 3 crystals.
Host rock is black shale.

[Fiebre Verde]

Doubly terminated quartz are not commonly seen in the Colombian emerald belts.
Note that the beryl crystal is also terminated.

The little story behind this specimen is pretty common.
The dealer had a small lot of high quality thumbnail specimens which he had on deposit from a comisionista (Local name for the emerald brokers in Colombia - owners rarely sell directly their goods).
Even after buying the lot, I could never get hold of the comisionista's name and even less the owner's name...
Sources are jealously protected specially in the small market of Bogota - nothing really surprising here.
Makes the hunt a bit more challenging (and pricey).

[Fiebre Verde]

Very likely from La Pava which is the westernmost mine of the Muzo mining district.
Host rock is black shale.

[Fiebre Verde]

This Chivor specimen is very likely from San Gregorio mine.

I have seen the black opaque crystal with sharp edges featured in the last image on several Chivor specimens but can't figure out what it is. A Dolomite rhomb?

Host rock is a crumbly grey shale.

[Fiebre Verde]

Another little aggregate from Coscuez.
No host rock.

[Fiebre Verde]

Host rock is gray shale.

[Fiebre Verde]

This aggregate was sold to me as from Chivor but the vivid grass-green coloration makes me think that it's actually from the La Pita mining district.

Out of the three chromophoric elements (V, Cr, Fe) of natural emeralds, only vanadium and chromium are found in significant concentration in Colombian emeralds.
Various studies have shown that the ratio of V/Cr is much higher in the La Pita emeralds than in any of the other Colombian districts.
The high concentration of vanadium versus chromium is responsible for the grass-green coloration of the La Pita emeralds.

[Fiebre Verde]

A Cunas specimen with a doubly terminated beryl crystal.
This locality has been continuously producing spectacular specimens over the past 12-13 years.
Not sure about the smoked crystals contained in the vug (2 last pictures). Quartz?