The Chalk Emerald is a 37.82 carat (7.564 g) Colombian emerald.

It originally weighed 38.40 carats (7.68 g), but was recut and set in a ring, where it is surrounded by sixty pear-shaped diamonds (totalling 15 carats (3 g)), by Harry Winston Inc. The ring is housed in the National Gem and Mineral Collection at the Smithsonian Natural History Museum in the United States and was donated to the museum by Mr. and Mrs. O. Roy Chalk in 1972.

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