The Chalk Emerald is a 37.82-carat Colombian emerald. Meanings of carat or karat: In the gem business: Carat (mass) is a unit of mass for gems. ... Emerald (Be3Al2(SiO3)6) is a variety of the mineral beryl, colored green by trace amounts of chromium and sometimes iron. ...

It originally weighed 38.40 carats, but was recut and set in a ring, where it is surrounded by sixty pear-shaped diamonds (totalling 15 carats), by Harry Winston Inc. The ring is housed in the National Gem and Mineral Collection at the Smithsonian Natural History Museum and was donated to the museum by Mr. and Mrs. O. Roy Chalk in 1972. This article does not cite its references or sources. ... The Smithsonian Institution Building or Castle on the National Mall serves as the Institutions headquarters. ... The museum as seen from the National Mall, the Old Post Office Building visible in the distance National Mall museum entrance The National Museum of Natural History is a museum administered by the Smithsonian Institution, located on the National Mall in Washington, D.C. The museums collections total over...

External links

• http://famousdiamonds.tripod.com/chalkemeraldring.html
• http://www.ks.uiuc.edu/~tskirvin/pics/trips/DC-2006/NaturalHistory-2006.02.20/tn/img_2330.jpg.html
• http://www.palmbeachdailynews.com/comm/content/news/chalkobit514.html