Emeralds are popular gems that commonly are used in jewellery and ornaments. It is the traditional birthstone of May. The emerald, a variety of the mineral known as beryl, can be identified through a few simple observations. The most common and easiest characteristics to identify are colour, lustre, streak, and hardness.
Look at your sample to see what colour it is. Emeralds are green, although the hue may vary.
Examine to see if your sample has a vitreous lustre. Light should reflect off the surface of the mineral to give it a glassy look.
Rub the mineral firmly across a porcelain streak plate. It is recommended that you choose a dark-coloured streak plate. An emerald will leave a white streak.
Test the hardness by carefully attempting to scratch it with a steel knife and an emery cloth. According to the book, "Rock and Gem", Emeralds have a hardness of 7.5 to 8 on the Mohs' hardness scale, meaning that they are relatively resistant to scratches. A steel knife will not scratch an emerald, but an emery cloth will.
Testing your gem may cause damage. Be careful!