Moh's hardness: 7.5- 8
The name emerald comes from the Greek 'smaragdos' via the Old French 'esmeralde'. It means 'green stone'. Emerald is the most precious stone in the beryl group, which also includes aquamarine, morganite and precious beryl. In top quality emeralds are even more valuable than diamonds. Since ancient times emeralds have been highly admired gems. The Incas and Aztecs regarded the emerald as a holy gemstone. The oldest known finds of emerald were made near the Red Sea in Egypt where gems were mined by the pharaohs between 3000 and 1500 B.C.
The vivacious brilliance of the emerald's green color makes this gem unique. High quality emeralds are quite rare as inclusions often cloud their interior. This is the main reason is why fine emeralds are so valuable. Slight inclusions however, do not necessarily diminish their value. On the contrary, even with inclusions, an emerald in a deep, lively green still has a much higher value than an almost flawless emerald whose color is paler. Emeralds from Zimbabwe are among the oldest gemstones in the world. They were already growing deep within the earth 2600 million years ago. Colombia, where the Incas mined these green gems in pre-Columbian times, is still at the top of the list of countries where fine emeralds are found. Fine emeralds are also found in Zambia, Brazil, Zimbabwe, Madagascar, Pakistan, India, Afghanistan and Russia.
Emeralds have a good hardness that protects them from scratches, but the stone is fairly brittle and sensitive to knocks. Therefore, a special step cut was developed to protect emeralds from mechanical strain. The 'emerald cut' is a clear design that can be rectangular or square with truncated corners. Today many emeralds are enhanced with colorless oils or resins that seal the fine pores in the surface of the gem. Removing these substances will end up giving the stone a matt appearance. For this reason, emerald jewelry should never be cleaned with ultrasonic method and should never be worn in water containing cleansing agents.