Emerald (from Vulgar Latin: esmaralda/emsaraldus a variant of Latin smaragdus which originated in Greek: smaragdos "green gem") is the green variety of beryl.
Colour is divided into three components: hue, saturation and tone. Emeralds occur in hues ranging from yellow-green to blue-green, with the primary hue being green. A fine emerald must possess not only a pure verdant green hue, but also a high degree of transparency to be of the highest quality.
The first known emerald mines were in Egypt, dating from at least 330 BC into the 1700s. Cleopatra was known to have a passion for emerald and used it in her royal adornments.
Colombia is by far the world's largest producer of emeralds, constituting to 50-95%, and their characteristics set the highest standards of quality. Zambian emerald, darker than Colombian, are a close second. Brazilian emeralds are typically brighter due to them having a slight brown or gray cast and only sometimes match the pure green hue that many Colombian offer.
Wearing an emerald was believed to reveal the truth or falseness of a lover's oath as well as make one an eloquent speaker. Legend also states that emerald was one of the four precious stones given by God to King Solomon. These four stones were said to have endowed the king with power over all creation. Its colour reflects new spring growth, which makes it the perfect choice of a birthstone for the month of May. It's also the gemstone for twentieth and thirty-fifth wedding anniversaries.
The Chalk Emerald weighs 37.80-carats and is in the collection of the Smithsonian National Museum of Natural History. - Chip Clark, courtesy Smithsonian Institution.
The 75.47-carat Hooker Emerald was worn by Ottoman Sultan Abdul Hamid II, the last sultan of the Ottoman Empire.National Museum of Natural History.