Crystal Characteristics of Colombian Emerald Specimens
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. A good example of
this tabular type formation is a specimen from John Barlow's
collection called
El Silencio.
It was
named "El Silencio" because it came from a corte in
Cosquez of the same name.
El
Silencio-Photo by Jeff Scovil © 1996-2006
Emeralds.com
Another example of a multiple aggregate type formation is a
spcecimen that was on a recent cover of the "The
Mineralogical Record" (from Corte 35 in Coscuez). We called
this specimen
La Cresta because
the crystal formation appeared similar to the crest on a
roosters head.
La
Cresta-Photo by Jeff Scovil © 1994-2006
Emeralds.com
Using color alone would make the identification process very
difficult. The emerald crystals in Coscuez tend to exhibit a
very wide range of colors and also tend to be more included.
Emerald crystals from Muzo tend to have more saturated color
than either Coscuez or Chivor.
Chivor emeralds are
best known for their bluish caste and generally have much
less inclusions and lighter color than either Coscuez or
Muzo. It must be stressed again that color alone in many
instances will provide no clues in regards to origin.
In terms of size and shape, the emerald crystals from Muzo
tend to be shorter with a lesser likelihood of termination
and clustering. The crystals from Chivor frequently occur
shaped like long thin pencil leads.