Emerald has a Mohs hardness of 7.5 to 8, which is normally a very good hardness for jewelry use. However, most emeralds contain numerous inclusions or surface-reaching fractures. These can weaken the gem, cause it to be brittle, and make it subject to breakage.

These are expected characteristics of emerald. It is rare to find an emerald that does not have inclusions and surface-reaching fractures that can be seen with the unaided eye. Under low magnification, most emeralds are said to have a “garden” of inclusions.

To improve appearance, most cut emeralds are treated with oils, waxes, polymers, or other substances that enter the fractures and make them less obvious. Although these treatments might improve appearance, they often do not improve the durability of the gem and they may discolor or deteriorate over time.

With that information, emerald should be considered a fragile stone that is best worn as a ring stone on special occasions rather than daily. Emerald is better suited for earrings and pendants that are usually subjected to less impact and abrasion than rings and bracelets. Settings that protect the stone are much safer than those that present the stone to impact and abrasion.

Cleaning emeralds should be done carefully. Steam and ultrasonic cleaning can remove oils and other fracture-filling treatments. A light washing in warm water with a mild soap is safer for cleaning and should be done only when needed.