About Colombian Emeralds

Characteristics of Emerald Specimens from Colombia

Colombia contributes with around 50% of world production of Emeralds and more than 80% of the finest emeralds are mined in Colombia. The mining areas are:

Western Emerald Belt: Muzo, Coscuez, Plenas Blancas,Quipama, Yacopi
Eastern Emerald Belt: Chivor, Gachala, La Pita, Totumos, Guavio

Out of these, there are three main Emerald mining areas in Colombia: Muzo, Coscuez, and Chivor.

Colombian government consortiums have been leasing Muzo and Coscuez mines for the past few decades, whereas Chivor is privately owned. Muzo and Coscuez are much more prolific in production, thus the majority of the specimens we sell are from these two areas.

The best way to differentiate emerald specimens from these three origins is by carefully examining the individual characteristics of the crystals and the matrix.

Crystal Characteristics

1. Colour: The emerald crystals in Coscuez tend to exhibit a very wide range of colours and also tend to be more included. Emerald crystals from Muzo tend to have more saturated colour than either Coscuez or Chivor. Chivor emeralds are best known for their bluish caste and generally have much less inclusions and lighter colour than either Coscuez or Muzo. Colour alone in many instances will provide no clues in regards to origin, making the identification process very difficult.

The most obvious distinction between crystals from these areas is that the Coscuez crystals have a frequent occurrence of aggregate type formations with multiple terminations. These aggregates will very often have a stepped-like look and sometimes take on a tabular appearance.
Famous example are "El Silencio" (Named after a cut in Coscuez of the same name), from the John Barlow's collection, and  "La Cresta" (named after the similarities of the crystal formations with the crest on a roosters head). This one shows a multiple aggregate type formation which appeared on a cover of the "The Mineralogical Record" (from Corte 35 in Coscuez).

2. Size and shape>: Emerald crystals from Muzo tend to be shorter with a lesser likelihood of termination and clustering. The crystals from Chivor are oftenly shaped like long thin pencil leads.

Matrix Characteristics

The typical Colombian emerald matrix is predominately formed by black and grey shale, white and grey calcite, and pyrite.
Muzo, Coscuez and Chivor specimens exhibit many of the same elements in their respective matrixs'. It is the different combinations of these materials that helps in distinguishing them from each other.

Coscuez: grey calcite tends to be the most predominant characteristic of this mine matrix material. Black shale in combination with either grey calcite or a rust coloured layer of iron oxide or a gray calcite matrix by itself are the most common combinations found . Also thin veins of pyrite running through the black shale is quite common rather than crystallized nodules of pyrite. The photos of La Dosita and El Jardin are great examples of Coscuez emerald specimens.

Muzo: this matrix is usually formed by  three elements ( white calcite, crystallized pyrite and clear quartz ) combined with the ever-present black shale.
White calcite and crystallized pyrite are quite common with clear quartz being relatively rare. "La Cruz" from the collection of Joe and Ann Ondraka is a classic Muzo specimen, easily identified by the white calcite and crystallized pyrite in its matrix. The beautiful dark green color and bluish tint of the crystals are also typical of the El Indio corte (part of the Puerto Arturo area which produces the best quality emeralds in Muzo).

Chivor: is the smallest of the three and is separate from Muzo and Coscuez which are adjacent to each other. The matrix material from Chivor tends to be much more fragile and "crumbly" in nature. Typically it is brown in color and is a brecciated mixture of calcite with layers of iron oxide. Iron stains are very common. Another type of matrix quite common in Chivor is a grey almost marble looking shale. Chivor like Muzo, frequently has crystallized nodules of pyrite occurring on the martix. Because production in Chivor is sporadic and because the matrix material tends to crumble, fewer intact specimens are found. El Primero is an excellent example of a Chivor emerald specimen.

All three areas have many identical features in their matrix and crystal forms. But with careful inspection and examination of both the matrix and crystal properties, it can usually be readily determined from which area the particular Emerald specimen is from.
La Pita mine is currently producing some specimens of excellent quality, that’s the reason why we now have incorporated their emeralds to our stock and have them readily available for our customers. We will gladly identify the mine where it comes from with each emerald we sell.