Part of the beryl family, the emerald has traces of chromium and vanadium which are responsible for the fascinating color. Normally, these two elements are concentrated in different parts of the Earth's crust to beryllium, so the emerald should, strictly speaking, not exist at all. But during intensive tectonic processes such as orogenesis, metamorphism and erosion of the land, these contrasting elements found each other and crystallized out to make one of our most beautiful gemstones.
The emerald’s hardness protects it from scratches, but its brittleness and many fissures can make cutting, setting and cleaning rather difficult. The high value of the raw crystals and the frequent inclusions makes cutting emeralds especially challenging. Gem cutters have developed a special cut just for this gem, naturally, called the emerald cut. The clear design of this rectangular or square cut with its beveled corners brings out the beauty of this valuable gemstone and protects it from mechanical strain.
Today, many emeralds are enhanced with colorless oils or resins. This is a general trade practice, but it does have the consequence that they react very sensitively to inappropriate treatment. For example, they cannot be cleaned in an ultrasonic bath. The substances that may have been used by the cutter during his work, or applied subsequently, seal the fine pores in the surface of the gem. Removing them will end up giving the stone a matte appearance. For this reason, emerald rings should always be taken off before hands are submerged in water containing cleansing agent.
Only seldom will a large emerald with good color and good transparency be found. That is why fine emeralds are so valuable. In top quality, fine emeralds are even more valuable than diamonds.
One of the world's largest is the so-called 'Mogul Emerald'. Found in 1695, it weighed 217.80 carats and was 10cm tall. Prayer texts are inscribed on one side and magnificent floral ornaments on the other side. This legendary emerald was auctioned by Christie's of London to an unidentified buyer for $2.2 Million on September 28, 2001.
Brazil is one of the largest volume producers of emerald in the world, and the states of Minas Gerais, Bahia, and Goias have the largest deposits in the country. Significant emerald deposits in Minas Gerais are found at the Capoeirana mine and Itabira mine in Nova Era, Municipio Itabira. Brazil has been known to produce large rough emeralds up to 200 carats in size.