Emeralds belong to the beryl mineral family and are recognized with a rich, distinctly green color. A pure beryl is colorless and are labelled as ‘goshenite.’ However, the presence of trace amounts of chromium or vanadium (Colombian emeralds) enable the development of a green color. Additionally, trace amounts of iron result in green shades more at the bluish side of the spectrum. These gemstones are mined in Colombia, Zambia, Brazil, Ethiopia, and Zimbabwe. On the Mohs scale of mineral hardness an
emerald measures a 7.5 to 8. As these stones do not rank high on the Mohs scale, they tend to contain numerous inclusions or surface-reaching fractures which weaken the gem and make it brittle, making it more prone to breakage.
A rare variety of emeralds, identified as the trapiche emeralds, can be found in the few mines of Colombia. These exhibit a six- sided, zoned morphology.
As emeralds are commonly found with surface breaking fissure, these gemstones are often enhanced through treatments. Most emeralds are oiled in order to fill in surface- reaching cracks; cedar oil is most widely used for this treatment. However, treated emeralds are worth less than untreated emeralds of similar quality
Synthetic gemstones are lab-produced gemstones and are produced by flux and hydrothermal processes.
These stones have the same chemical composition and crystal structure as natural emeralds and have superior clarity. Even so, natural emeralds would have a higher market value than synthetics. Synthetic emeralds can be distinguished by their refractive index(RI) and microscopic examination by an experienced gemologist; they have a lower RI than natural emeralds. Aside from synthetics, imitation emeralds are stones which have a similar physical appearance to emeralds (however different chemical
composition) and may serve as a cheaper substitute: green glass, synthetic green spinel, green cubic zirconia, and green yttrium aluminum garnet.
