Color: Green from trace amounts of chromium and sometimes vanadium.
Hardness: 7.5-8 Mohs scale
Emerald is a member of the beryl family.
Emeralds are graded by eye. Due to the number of inclusions and surface breaking fissures, if no visible inclusions are visible, then it is considered flawless.
Stones that have slight flaws are treated with oil like cedar oil (due to having a similar refractive index). Other liquids, synthetic oils and polymers with the refractive index close to the emerald are also used. Another common liquid is Opticon.
Gems are graded on a four-step scale; none, minor, moderate and highly enhanced. These categories reflect levels of enhancement, not clarity. A gem graded none on the enhancement scale may still exhibit visible inclusions. Laboratories tend to apply these criteria differently. Some gem labs consider the mere presence of oil or polymers to constitute enhancement. Others may ignore traces of oil if the presence of the material does not materially improve the look of the gemstone
Emeralds were mined in Egypt since 1500 BCE, and India and Austria since as early as the 14th century.
Today, Columbia is the largest producer of emeralds with three main mining areas; Muzo, Coscuez, and Chivor. Zambia is the second largest producer of emeralds. Here in the US, emeralds are found in North Carolina, South Carolina, Connecticut, Montana and Nevada.
Chalk Emerald: Was originally part of the royal coffers of the Baroda State in India. It had been originally set in a diamond necklace worn by Maharani Saheba, who passed it dowon to her son, the Maharajah Cooch Behar. It was recut from 38.40 carats to 37.82 carats and set into a ring with 15 carats of diamonds surrounding it. It was donated to the Smithsonian Institution’s National Museum of Natural History in 1972. It is displayed prominently next to the Hope diamond. Emerald came from Columbia, SA.
Jorfer- public release for use 2007
The Duke of Devonshire Emerald: The Devonshire Emerald was discovered in the early 19th century in the region of Muzo, Colombia, known for its fine colored emeralds with characteristic blue overtones. Weighing 1,383.95 carats with a height of about 2 inches, it is said to be one of the largest and finest rough Emeralds in the world.
The Duke of Devonshire Emerald
Gachalá Emerald: The Gachala emerald was found in the town of Gachala in Columbia, SA, in 1967. The emerald weighs 858 carats and is considered to be one of the most beautiful emerald gemstones known.The stone eventually ended up in the hands of Harry Winston, a jeweler in New York city. He donated the gemstone to the Smithsonian Institution. In 1958, Harry Winston donated the Hope diamond to the Smithsonian.
Mogul Mughal Emerald: This is one of the largest engraved emeralds. Weighing in at 217.80 carats, the rectangular cut stone is engraved with the Shi’a invocation in a naskh script. It has been dated back to 1107. The reverse side has a central rosette flanked by large poppy flowers.
It was sold September 27, 2001 by Christie’s for about $2 million dollars US.
Mogul Mughal Emerald
The Patricia Emerald: This stone weighs in at 632 carats. It is a natural uncut stone of Columbian origin. It got it’s name from the daughter of the man who owned the mine in Chivor, Columbia. It is a rare bi-hexagonal crystal with 12 sides. It was found in 1920.
The Patricia Emerald
Bahia emerald: This is a mass of emerald crystals from a Brazilian mine. The mass is over 840 pounds with 180,000 carat emerald crystals. The stone came from Bahia, Brazil. Ownership of the stone has been a much debated affair. It is aid to have been stolen on more than one occasion. In a court ruling on June 23, 2015, it was determined that FM Holdings, LLC was the bona fide owner of the Bahia Emerald. However, on June 25, 2015, a restraining order protecting the stone was issued, arguing that the stone is subject to forfeiture in Brazil since they are contesting it saying it was smuggled out of the country there. It has not been resolved yet.