Definition of: diamond

(dī′mənd, dī′ə-) noun
1. A mineral of great hardness and refractive power, consisting of carbon crystallized in the isometric system under great pressure and temperature. When pure it is a valuable gem with a beautiful display of prismatic colors, especially when cut. See list below.
2. A natural crystal face of this stone, used in cutting glass, etc.
3. Geom. A figure bounded by four equal straight lines, and having two of the angles acute and two obtuse; a rhomb or lozenge.
4. Printing A size of type next above brilliant; 4– or 4 1/2–point.
5. A lozenge–shaped spot on a playing card, or a card or (in the plural) suit so marked.
6. The square enclosed by the lines between the bases on a baseball field.
—v.t. To adorn with or as with diamonds. [<OF diamant <LL daimas, -antis, alter, of L adamas. Doublet of ADAMANT.]
—dia′·mond·ed adjective
FORMS OF CUT DIAMONDS
a. b. c. Brilliant cut.
d. Marquise cut.
e. Pitt or regent cut.
f. Kohinor cut.
g. Double rose (side view) cut.
h. Rose cut.
i. Briolette cut.

—Cullinan diamond
The world's largest diamond, 3,106 metric carats, discovered in South Africa, 1905, and named for Sir T. M. Cullinan: cut into several pieces, one set in the British scepter, one in the crown: presented to King Edward VII and renamed by King George V the Star of Africa.
—Great Mogul diamond
An Indian diamond found about 1650 and said to have weighed 787 carats: named when the diamond was part of the treasure of the Mogul court. The second largest diamond, it has since disappeared.
—Hope diamond
A blue diamond, the largest and most celebrated of the colored diamonds, 44.5 carats: named for Sir H. T. Hope, one of its owners.
—Jonker diamond
The world's fourth largest diamond, 726 metric carats, found in South Africa in 1934 by Jacobus Jonker.
—Koh–i–nor diamond
One of the British crown jewels, 186 carats in original cutting, dating back earlier than the 14th century: from the Persian meaning “mountain of light.”
—Vargas diamond
The world's third largest diamond, 726.6 metric carats, found in Brazil in 1938: named for President G. D. Vargas of Brazil.