Emerald sources in Colombia
History of Muzo
Colombian emeralds are located in an area known as the ‘Emerald Belt’ of the Cordillera Oriental in the Gobernación de Boyacá and Cundinamarca district. One major mining area was the Vasquez-Yacopi mining district, which included the Muzo mine and the city of Muzo founded by Luiz Lancheron in 1555. From the first mining operation by the Spaniards in 1558 until the present day, many different mining operations, such as Jose Ignacio Paris, Sociedad la Nueva Granada, Ecominas and Sociedad Minera Boyacense, have worked this area. There have also been joint ventures between privately owned enterprises and public organisations.
Characteristics of Muzo Mine
This colour is the most prestigious green, said to be that of a particular butterfly (mariposa in Spanish) which occurs only in the Muzo area.
Crystal characteristics of Muzo emeralds
These crystals do not form clusters or aggregates. However, Muzo emeralds tend to be shorter than those from Chivor. Muzo emerald crystals tend to have a more saturated colour.
History of Coscuez Mine
The deposits were exploited by natives long before the arrival of Europeans in the 16th century. Emeralds did not become common in world trade until after the Spaniards had reopened the ancient mines. In 1886 the Colombian constitution proclaimed Coscuez the property of the nation. However, mismanagement and illegal mining forced the government to lease out the Coscuez area to a private mining company, ESMERACOL. The main area was stripped away very rapidly so that a significant portion of the potential emerald production was lost to the Rio Itoco. In times of peak production, around 15,000 guaqueros (independent miners) worked this area every day.
Characteristics Coscuez Mine
The colour of the emeralds from the Coscuez mine is bright green with a yellowish undertone. The appearance of the emerald is translucent and some cracks and fissures are visible. Emeralds from Coscuez generally have fewer inclusions than those from Muzo.
Crystal characteristics of Coscuez emeralds
Certain characteristics of the crystal and matrix can be used to identify the source of the emeralds from Coscuez. The most characteristic feature is their frequent occurrence in aggregate-type formations with multiple terminations. The emerald crystals from Coscuez are longer than those from Muzo but shorter than those from Chivor.
Color differences and inclusions in emeralds from Coscuez.
Emeralds from Coscuez generally have good transparency with a bright yellowish-green colour. It may not be possible to predict the source of these emeralds correctly from the colour alone. Coscuez emeralds have diffuse jardins and inclusions.
Matrix characteristics of Coscuez emeralds
Coscuez emeralds occur in black and grey shale, white and grey calcite and pyrite. The combination of these components differs with each source. In the Coscuez matrix the most predominant characteristic is the presence of grey calcite.
History of Chivor Mine
Chivor, formerly Somondoco, is the oldest mine in Colombia and is situated north-east of Bogotá.
In 1537, Gonzalo Jimenez de Quesada conquered the interior of Colombia, locating the mine area which was worked by the Chibcha Indians. From 1540 until 1675 the mine was operated under incredibly harsh conditions and finally closed down.
After 1828 the Colombian government leased the mine out. From 1911 the German Fritz Klein and his associate Don Francisco Restrepo worked it for a couple of years.
From 1915 to 1931 the mine was worked under a new joint venture, the ‘Sociedad Ordinaria de Minas des Esmeraldas de Chivor’.
From 1936 to 1996 the mine was operated sporadically.
Starting in 1996, a Canadian company called the Chivor Emerald Corp. worked the mine for some time using sophisticated computer-aided mining methods.
Characteristics of Chivor Mine
Chivor emeralds are famous for their colour, which shines even more strongly when they are held in half-light.
Crystal characteristics of Chivor emeralds
Crystals from Chivor are always longish and do not form clusters or aggregates.
Color differences and inclusions in emeralds from Chivor
Chivor emeralds have a lighter bluish-green colour and generally far fewer inclusions than Muzo emeralds. They have three-phase inclusions containing gas, fluid and crystals of halite together with pyrite and albite.
Matrix characteristics of Chivor emeralds
In the matrix of Chivor emeralds greyish shale is combined with grey calcite and layers of iron oxide and crystallised knots of pyrite. The matrix is fragile and has brown stains caused by iron oxide. Because of this fragility, fewer specimens with the matrix still intact are found in Chivor.