The Muzo mine comprises several emerald
-bearing areas. The main area, the Tequendama
quarry, has been mined for more than 300 years.
crystals usually occur in small cavities and vugs, in bulges of calcite veins where the veinlets intersect, and in the vein selvages in vugs ("pockets") in the country rocks, which are connected with the veins by thin carbonate or albite veinlets. The emerald
is initially associated with coarse-grained dolomite and parisite. Emerald
crystals are also disseminated in the black shales near calcite veins and contain numerous relict particles of the coaly material, which supports a metasomatic origin.
from the veins and "pockets" in the shales are represented by prismatic often short-columnar crystals to 3 cm long. Larger emeralds
, some as much as 15 cm in length, are occasionally recovered. Some are of very high gem quality and have established worldwide recognition for the Colombian emeralds
(example is Devonshire emerald
- 1384 carats).
colour varies from light green to bright and deep green, it depends on the content of chromophore admixtures. Muzo emeralds have a yellowish tint. Solid inclusions in emerald
are very fine particles of carbonaceous matter.
Ref: E.Ya. Kievlenko (2003) Geology of gems, pp. 99, 100, 101
Gem list contains entries from all listed localities in region.
Gemstones from Muzo Municipality, Boyacá Department, Colombia by Colour
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Localities in this Region