The DeYoung Red Diamond is a 5.03- carat unmounted rare red

diamond Diamond is a solid form of the element carbon with its atoms arranged in a crystal structure called diamond cubic. Another solid form of carbon known as graphite is the chemically stable form of carbon at room temperature and pressure, ...

. It is the third-largest red diamond in the world, and the only one on public display. Sydney DeYoung (for whom the diamond is named) obtained the diamond, which was mistaken for a

garnet Garnets () are a group of silicate minerals that have been used since the Bronze Age as gemstones and abrasives. All species of garnets possess similar physical properties and crystal forms, but differ in chemical composition. The different s ...

, at a flea market. The diamond was given to the

Smithsonian Institution The Smithsonian Institution ( ), or simply the Smithsonian, is a group of museums and education and research centers, the largest such complex in the world, created by the U.S. government "for the increase and diffusion of knowledge". Founded ...

after DeYoung's death in 1986.

Description

The DeYoung Red Diamond is a 5.03- carat unmounted diamond. It is a deep red

color Color (American English) or colour (British English) is the visual perceptual property deriving from the spectrum of light interacting with the photoreceptor cells of the eyes. Color categories and physical specifications of color are assoc ...

, with a slight tint of brown. Red diamonds are the rarest type of colored diamonds. The diamond is a modified round

brilliant cut A brilliant is a diamond or other gemstone cut in a particular form with numerous facets so as to have exceptional brilliance. The shape resembles that of a cone and provides maximized light return through the top of the diamond. Even with moder ...

. The facets on the diamond's crown, which resemble

kite A kite is a tethered heavier-than-air or lighter-than-air craft with wing surfaces that react against the air to create lift and drag forces. A kite consists of wings, tethers and anchors. Kites often have a bridle and tail to guide the fac ...

s, are split in two horizontally. This feature makes the DeYoung diamond more brilliant than other diamonds with an ordinary round brilliant cut. The DeYoung Red Diamond is the third-largest red diamond, behind only the 5.05-carat Kazanjian Red Diamond (second-largest) and the 5.11-carat

Moussaieff Red Diamond The Moussaieff Red Diamond (formerly known as the Red Shield Diamond) is a diamond measuring 5.11 carats (1.022 g) with a triangular brilliant cut (sometimes called a trillion or a trilliant cut), rated in color as Fancy Red by the Gemological In ...

(largest). Its clarity grade is VS-2 (Very Slightly Included). The diamond is a Type IIa diamond, meaning that it does not have any chemical impurities. Type IIa diamonds comprise only 1–2% of all naturally occurring diamonds.

Ownership

The diamond was purchased at a flea market by Sydney DeYoung (1897–1986), a

Boston Boston (), officially the City of Boston, is the state capital and most populous city of the Commonwealth of Massachusetts, as well as the cultural and financial center of the New England region of the United States. It is the 24th- mo ...

jewelry seller. The diamond, which was mistaken for a

, was on a

hatpin A hatpin is a decorative and functional pin for holding a hat to the head, usually by the hair. In Western culture, hatpins are almost solely used by women and are often worn in a pair. They are typically around in length, with the pinhead be ...

being sold as part of an estate jewelry collection. Upon later examining the stone, however, DeYoung noted that it was of unusually high quality for its age and did not have the appearance of a garnet. He had it tested at a gem-testing laboratory, and it was discovered that the stone was actually a red diamond. After DeYoung's death in 1986, the diamond was given to the

National Gem and Mineral Collection The National Museum of Natural History is a natural history museum administered by the Smithsonian Institution, located on the National Mall in Washington, D.C., United States. It has free admission and is open 364 days a year. In 2021, with 7 ...

, a part of the

National Museum of Natural History The National Museum of Natural History is a natural history museum administered by the Smithsonian Institution, located on the National Mall in Washington, D.C., United States. It has free admission and is open 364 days a year. In 2021, with 7 ...

, in accordance with DeYoung's wishes. The Smithsonian received the diamond in 1987; it was mailed to the Smithsonian uninsured in an ordinary box. The diamond, which is protected by

bulletproof glass Bulletproof glass, ballistic glass, transparent armor, or bullet-resistant glass is a strong and optically transparent material that is particularly resistant to penetration by projectiles. Like any other material, it is not completely impenetr ...

in the Hall of Gems, is the only red diamond on public display; all the others are privately owned. Another diamond given by DeYoung in 1962, a 2.90-carat pear-shaped pink diamond obtained from Williamson mine in

Tanzania Tanzania (; ), officially the United Republic of Tanzania ( sw, Jamhuri ya Muungano wa Tanzania), is a country in East Africa within the African Great Lakes region. It borders Uganda to the north; Kenya to the northeast; Comoro Islands ...

, is displayed alongside the red diamond.

References

{{Reflist Red diamonds Collection of the Smithsonian Institution Individual diamonds

Description

Ownership

See also

References