Concave Features in Emeralds
When emeralds are polished, the polisher does not always remove all traces of the stone’s original form. Emeralds are frequently cut with a little part from their unpolished form showing someplace on the girdle (middle) or pavilion (bottom). Basically nowhere that can be seen from the crown, and will most likely be obscured in a setting. They are not an inclusion either since inclusions by definition form inside the stone instead of a surface feature of the uncut crystal. Features that are only “skin deep” in gems are referred to as blemishes.
While leaving a remnant of the emerald’s original form is not always possible, this usually serves as an indication that it formed naturally. It is also a way for the cutter to show they used the maximum amount of the crystal rough they could, a testament to their skill.
Sometimes the remnants are more or less flat along the gem’s surface, sometimes they are slightly indented into the gemstone and concave. They are formally referred to as “naturals” since they are pieces of the gem before being transformed by human hands. These concavities can be polished out along with other alterations to the gem cut at the buyer’s request. With each polishing there are varying losses of carat weight, so bear that in mind before deciding to re-cutting a gem.
On the left above is a pre-formed gemstone rough that has been prepared to be faceted. Notice how there are no other rock formations on the rough. On the right is an example of a cut emerald produced from a similar piece of rough.
Usually there is no reason for these natural indentations to be removed if the features are not causing visual or structural problems. For example, E1629 looks fine when you look down through the crown of the gem. There is only one of these natural indentations on a small spot in the back. This feature will really not be visible once set in a piece of jewelry.
E1629 | medium | play | left | “Emerald ID: E1629 Weight: 6.66 Carats Origin: Zambia”
