A remarkable bi-colour Beryl gemstone from the Novo Era mine, Minas Gerais, Brazil.

The gem is mostly colourless, which would lead to a description of Goshenite, the colourless variety of the Beryl Family.
However, the gem also displays thick bands of bright green which is due to the presence of Chromium and Vanadium in the growth environment of the Beryl crystal during a certain point in its formation, meaning that this section is technically Emerald.
Image 4 is a slightly magnified image of the stone held against a white background and viewed through its rear facets where the interface between the green and colourless section is most clear, although the phenomenon is also visible through its table and upper facets.

Part-colour Emerald of this type is rarely encountered as a faceted gemstone, with this fine example having excellent clarity.

weight:  1.80 carats
shape:   Rectangular baguette cut
dimensions:   9.61 x 5.90 x 4.07 mm
treatment:  None