This process optically eliminates "feathers" (inclusions), which are naturally occurring imperfections found in most diamonds.
If a buyer requests additional gem testing prior to a sale, the seller may provide this, but at additional cost to the buyer.
Lastly, the gemologist estimates the saturation level. Saturation is also where any additional colors such as those due to color change, pleochroism, color zoning, and windowing less than 50% are noted.
Saturation has a moderate to strong effect on appearance.
Many of the gems we offer are "Natural" and "untreated", but the majority of the gems on the market are routinely enhanced or treated in some way, so we have always been concerned in disclosing any treatments that we know may exist as well as the affect it may have on the gem you are considering.
We disclose the particular treatment that may apply to a particular gem, both in our online description as well as at the point of sale.