E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
is really the mineral corundum; but the word is indifferently used for rock crystal, diamond, or any hard substance, and also for the magnet or loadstone. It is often used by poets for no specific substance, but as hardness or firmness in the abstract. Thus, Virgil, in his Æneid vi. 552, speaks of adamantine pillars merely to express solid and strong ones; and Milton frequently uses the word in the same way. Thus, in Paradise Lost, ii. 436, he says the gates of hell were made of burning adamant:
This huge convex of fire
Outrageous to devour, immures us round
Ninefold, and gates of burning adamant
Barred over us prohibit all egress.
Satan, he tells us, wore adamantine armour (Book vi. 110):
Satan, with vast and haughty strides advanced,
Came towering, armed in adamant and gold.
And a little further on he tells us his shield was made of adamant (vi. 255):
He [Satan] hasted, and opposed the rocky orb
Of ten-fold adamant, his ample shield
A vast circumference.
Tasso (canto vii. 82) speaks of scudo di lucidissimo diamante (a shield of clearest diamond).
Other poets make adamant to mean the magnet. Thus, in Troilus and Cressida, iii. 2:
As true as steel, as plantage to the moon,
As sun to day, as turtle to her mate,
As iron to adamant.
(Plantage to the moon, from the notion that plants grew best with the increasing moon.)
And Green says:
As true to thee as steel to adamant.
So, in the Arabian Nights, the Third Calendar, we read:
To-morrow about noon we shall be near the black mountain, or mine of adamant, which at this very minute draws all your fleet towards it, by virtue of the iron in your ships.
Adamant is a (negative) and damao (to conquer). Pliny tells us there are six unbreakable stones (xxxvii. 15), but the classical adamas (gen. adamant-is) is generally supposed to mean the diamond. Diamond and adamant are originally the same word.