Adamantine

Adamantine (pronounced ad-uh-man-teen, ad-uh-man-tin or ad-uh-man-tahyn)

(1) Made of adamant, or having the qualities of adamant; incapable of being broken, dissolved, or penetrated.

(2) Utterly unyielding or firm in attitude or opinion.

(3) In informal use, too hard to cut, break or pierce.

(4) Having the luster of a diamond.

1200-1250: From the Middle English adamantine (made of adamant; having the qualities of adamant (hard, unyielding, unbreakable, inflexible)), the vocative masculine singular of adamantinus, from the Ancient Greek adamántinos (hard as adamant), from ἀδάμας (adamas), (genitive ἀδάμαντος (adamantos)) (unbreakable, inflexible and literally “unconquerable, untameable”).  The modern English diamond is from adamas, via the Late Latin diamas and the Old French diamant.  The noun form was used to mean “the hardest material” (a synonym of adamantium).  The most obvious derivative in modern English is adamant.  In classical mythology, adamant was the word used to describe diamond and the meaning was aligned with “metal” to indicate the quality of extreme hardness and, over time, emerged the notion of adamant being used figuratively to allude to attitudes or opinions which were “hard”, the synonyms varying according whether the wish was to convey admiration or disapproval and they included: inflexible, intransigent, uncompromising, inexorable. unbending, firm, unyielding stubborn, obdurate.  Adamantine is a noun & adjective and adamantinely is an adverb; the noun plural is adamantines.

The cuts from the Cullinan Diamond: Cullinan 1 was the largest of the nine stones cut from the rough diamond.  The largest gem-quality rough diamond ever found, the Cullinan Diamond was found on 26 January 1905 in South Africa’s Cullinan mine.  The stone weighed 3,106.75 carats (21.91725 oz, 621.35 g).  The Cullinan was cut into nine smaller diamonds, the largest of which is named Cullinan I or Great Star of Africa which, at 530.4 carats (18.7 oz, 106.0 g) is the largest clear cut diamond in the world.

Lindsay Lohan’s engagement ring: The piece was described as a 6-carat cushion-cut diamond set on a classic diamond-accented platinum band.