Chalk Emerald

The Chalk Emerald is a Colombian emerald. 
The royal rulers of Baroda State, a princely state in India, once owned the emerald. It was the centerpiece of an emerald and diamond necklace worn by the Maharani Saheba, who passed it down to her son, the Maharajah Cooch Behar. 
In the 20th century, the emerald was recut from its original weight of and set in a ring designed by Harry Winston, Inc., where it is surrounded by sixty pear-shaped diamonds, totalling approximately . The ring was donated by Mr. and Mrs. O. Roy Chalk to the Smithsonian Natural History Museum in 1972 and is part of the Smithsonian's National Gem and Mineral Collection. 