Di"a*mond (?; 277), n. [OE.
diamaund, diamaunt, F. diamant, corrupted, fr.
L. adamas, the hardest iron, steel, diamond, Gr. ?. Perh.
the corruption is due to the influence of Gr. ? transparent. See
Adamant, Tame.] 1. A precious
stone or gem excelling in brilliancy and beautiful play of prismatic
colors, and remarkable for extreme hardness.
☞ The diamond is native carbon in isometric crystals, often
octahedrons with rounded edges. It is usually colorless, but some are
yellow, green, blue, and even black. It is the hardest substance
known. The diamond as found in nature (called a rough diamond)
is cut, for use in jewelry, into various forms with many reflecting
faces, or facets, by which its brilliancy is much increased. See
Brilliant, Rose. Diamonds are said to be of the
first water when very transparent, and of the second or
third water as the transparency decreases.
2. A geometrical figure, consisting of four
equal straight lines, and having two of the interior angles acute and
two obtuse; a rhombus; a lozenge.
3. One of a suit of playing cards, stamped
with the figure of a diamond.
4. (Arch.) A pointed projection, like
a four-sided pyramid, used for ornament in lines or groups.
5. (Baseball) The infield; the square
space, 90 feet on a side, having the bases at its angles.
6. (Print.) The smallest kind of type
in English printing, except that called brilliant, which is
seldom seen.
☞ This line is printed in the type called
Diamond.
Black diamond, coal; (Min.) See
Carbonado. -- Bristol diamond. See
Bristol stone, under Bristol. -- Diamond
beetle (Zoöl.), a large South American
weevil (Entimus imperialis), remarkable for its splendid
luster and colors, due to minute brilliant scales. --
Diamond bird (Zoöl.), a small
Australian bird (Pardalotus punctatus, family
Ampelidæ.). It is black, with white spots. --
Diamond drill (Engin.), a rod or tube
the end of which is set with black diamonds; -- used for perforating
hard substances, esp. for boring in rock. -- Diamond
finch (Zoöl.), a small Australian sparrow,
often kept in a cage. Its sides are black, with conspicuous white
spots, and the rump is bright carmine. -- Diamond
groove (Iron Working), a groove of V-section in
a roll. -- Diamond mortar (Chem.),
a small steel mortar used for pulverizing hard substances. -
- Diamond-point tool, a cutting tool whose
point is diamond-shaped. -- Diamond snake
(Zoöl.), a harmless snake of Australia (Morelia
spilotes); the carpet snake. -- Glazier's
diamond, a small diamond set in a glazier's tool, for
cutting glass.