Last updated on May 5, 2023
The Chalk Emerald is one of the world’s most remarkable gemstones, a velvety green jewel that captures the imagination with its beauty and history. This 37.82-carat rectangular step-cut emerald is renowned for its superb clarity and colour, ranking it among the finest Colombian emeralds in the world.
The Origin of the Chalk Emerald
The origin of the Chalk Emerald can be traced back to the Muzo region of Colombia, where some of the world’s finest emeralds are found. For at least a millennium before the arrival of the Spanish conquistadors in the 16th century, indigenous peoples had been mining and using emeralds in the region. The Spanish soon realized the value of the exquisite green crystals and gained control of the mines, leading to a significant trade of emeralds to Europe by boatloads.
Like many other Colombian emeralds, the Chalk Emerald was one of the gems shipped to India by the Spanish during the 16th and 17th centuries. The popularity of emeralds rose among European royalty, fueling a vibrant trade of these gemstones to the Middle East and India. The Mogul rulers in India had a particular affinity for emeralds and promoted a thriving industry of gem-cutting and jewellery. As a result, many finished pieces were traded back to Europe.
After its arrival in India, the ownership of the Chalk Emerald became uncertain and unrecorded. However, it is believed to have once been the centrepiece of an emerald and diamond necklace owned by Jagaddipendra Narayan, the Maharaja of Koch Bihar, India. The Maharaja claimed that the stone had been worn by his mother, Indira Devi, to various state functions.
The exact journey of the Chalk Emerald from its mining in Colombia to its arrival in India and eventual sale to the British gem broker is shrouded in mystery. Still, the gemstone’s exquisite quality and rarity have made it a treasured part of the world’s gemstone heritage.
The History of the Chalk Emerald

In the mid-20th century, the gemstone eventually made its way to England. In 1959 the Maharaja sold the emerald to a British gem broker, and it was later purchased by the renowned American jeweller Harry Winston.
Winston recut the Chalk Emerald from its original weight of 38.40 carats (7.680 g) to its current weight of 37.82 carats (7.564 g) and created a gold setting to attach it to a platinum ring of his own design. He also surrounded the emerald with sixty pear-shaped diamonds, totalling 15.62 carats (3.124 g).
In 1962, the ring was sold to New York entrepreneur Oscar Roy Chalk for whom the emerald is now named, who gifted it to his wife Clair to wear to a state dinner at the White House in honour of Queen Elizabeth II. It is said that during the event, she discreetly turned the ring around so as not to outshine the Queen’s less impressive emerald ring.
In 1972, the Chalks donated the ring to the Smithsonian Institution, where it is now part of the National Gem and Mineral Collection on display in the Gem Gallery at the National Museum of Natural History in Washington, D.C.
The Chalk Emerald Characteristics
The Chalk Emerald is a stunning example of fine Colombian emeralds that are highly prized for their exceptional colour and clarity. With a weight of 37.82 carats (7.564 g), this rectangular step-cut gemstone displays a medium dark bluish green colour, highly prized among emerald connoisseurs.
In addition to its impressive colour, the Chalk Emerald boasts excellent transparency, allowing light to pass through the gemstone with ease. This characteristic, along with its attractive emerald cut, enhances the stone’s natural beauty and fire.
The Chalk Emerald is surrounded by 60 pear-shaped diamonds, weighing a total of 15.62 carats (3.124 g), further highlighting the emerald’s striking green colour. The diamonds serve as a stunning complement to the emerald, enhancing its brilliance and adding a touch of glamour to the ring’s design.
Overall, the Chalk Emerald is an exceptional example of a Colombian emerald, exhibiting all the desirable characteristics of this prized gemstone. Its velvety deep green colour, exceptional clarity, and impressive size make it a treasured part of the Smithsonian’s National Gem and Mineral Collection and a beloved symbol of the natural beauty of emeralds.
Featured image © Chip Clark, digitally enhanced by SquareMoose, Smithsonian Institution