Brazil has been producing a lot of just about everything for quite a while. For now, let's focus on the Queen of Gems - the Emerald.
As a faceter/cabber one of the biggest challenges I face is finding good rough at a reasonable price. Even small pieces of clean rough with good color can be very expensive. Most of the rough I see is moderately to severely included and/or very light. Sometimes I am willing to pay the price just to try my hand at a beautiful piece of precious gem rough. This makes using step cuts and deeper brilliant cuts for faceting the best choice despite the loss of brilliance.
Click on any of the pictures below to see a close-up shot of each view.
Cabbing material is often easier to find and a lot more affordable as with the two gems below. The stone on the left measures 18.0 x 12.1 mm and weights 13.35 carats.
Here are some of the beautiful crystals...
On the left is the better facet grade material, on the right is the cabbing rough.
I rough cut this material with a 360-grit plate, followed with a fine cut on a 1200-grit plate, and finished with a 14k polish. Remember to cut slowly and use plenty of water.
Although Emerald has a hardness of about 7.5 it tends to have internal fractures and cleavages making it susceptible to fracturing. Also, most emeralds are treated (usually with oil, resin, or epoxy) so cleaning them can risk removing the treatment.
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