Noun

Singular diamond

Plural diamonds

diamond (plural diamonds)

1. (uncountable) A glimmering glass-like mineral that is an allotrope of carbon in which each atom is surrounded by four others in the form of a tetrahedron.

   The saw is coated with diamond.

2. A gemstone made from this mineral.

   The dozen loose diamonds sparkled in the light.

3. A ring containing a diamond.

   What a beautiful engagement diamond.

4. A very pale blue color/colour.

   diamond color:

5. Something that resembles a diamond.
6. (geometry) A rhombus, especially when oriented so that its longer axis is vertical.
7. (geometry) The polyiamond made up of two triangles.
8. (baseball) The entire field of play used in the game.
9. (baseball) The infield of a baseball field.

   The teams met on the diamond.

10. (card games) A card of the diamonds suit.

    I have only one diamond in my hand.

11. (card games) (plural: diamonds) One of the four suits of playing cards.

    I have the eight of diamonds in my hand.

Synonyms

• (gemstone): sparkler (informal)
• (ring): diamond ring
• (something that resembles a diamond): adamant
• (geometry: rhombus): lozenge, rhomb, rhombus
• (geometry: polyiamond): 2-iamond
• (baseball: entire baseball field): ball field, baseball field
• (baseball: infield of a baseball field): baseball diamond, infield

Antonyms

• (baseball: infield of a baseball field): outfield

Derived terms

• baseball diamond
• blood diamond
• black diamond
• diamond anniversary
• diamonds are forever
• diamond geezer

• diamonds are a girl's best friend
• diamond jubilee
• diamond-shaped
• diamond wedding
• Killiecrankie diamond
• rough diamond

Related terms

• diamante

In mineralogy, diamond (from the ancient Greek ἀδάμας – adámas "unbreakable") is an allotrope of carbon, where the carbon atoms are arranged in a variation of the face-centered cubic crystal structure called a diamond lattice. Diamond is less stable than graphite, but the conversion rate from diamond to graphite is negligible at ambient conditions. Diamond is renowned as a material with superlative physical qualities, most of which originate from the strong covalent bonding between its atoms. In particular, diamond has the highest hardness and thermal conductivity of any bulk material. Those properties determine the major industrial application of diamond in cutting and polishing tools.

Diamond has remarkable optical characteristics. Because of its extremely rigid lattice, it can be contaminated by very few types of impurities, such as boron and nitrogen. Combined with wide transparency, this results in the clear, colorless appearance of most natural diamonds. Small amounts of defects or impurities (about one per million of lattice atoms) color diamond blue (boron), yellow (nitrogen), brown (lattice defects), green, purple, pink, orange or red. Diamond also has relatively high optical dispersion, that is ability to disperse light of different colors, which results in its characteristic luster. Excellent optical and mechanical properties, combined with efficient marketing, make diamond the most popular gemstone.

Most natural diamonds are formed at high-pressure high-temperature conditions existing at depths of 140 to 190 kilometers (87 to 120 mi) in the Earth mantle. Carbon-containing minerals provide the carbon source, and the growth occurs over periods from 1 billion to 3.3 billion years (25% to 75% of the age of the Earth). Diamonds are brought close to the Earth surface through deep volcanic eruptions by a magma, which cools into igneous rocks known as kimberlites and lamproites. Diamonds can also be produced synthetically in a high-pressure high-temperature process which approximately simulates the conditions in the Earth mantle. An alternative, and completely different growth technique is chemical vapor deposition. Several non-diamond materials, which include cubic zirconia and silicon carbide and are often called diamond simulants, resemble diamond in appearance and many properties. Special gemological techniques have been specially developed to distinguish natural and synthetic diamonds and diamond simulants.