As rock of diamond stedfast evermore.
Spenser, Fairy Queen, i. 6. 4.
Prince Arthur gave a boxe of diamond sure.
Spenser, ib. i. 9. 19.
Zeal, whose substance is ethereal, arming in complete diamond, ascends his fiery chariot drawn with two blazing meteors, figured like beasts, but of a higher breed than any the zodiack yields, resembling two of those four, which Ezekiel and St. John saw, the one visaged like a lion to express power, high authority, and indignation; the other of countenance like a man to cast derision and scorn upon perverse and fraudulent seducers; with these the invincible warrior Zeal shaking loosely the slack reins drives over the heads of scarlet prelates, and such as are insolent to maintain traditions, bruising their stiff necks under his flaming wheels.—Milton, Defence of Smectymnuus.
On each wing
Uriel and Raphaël his vaunting foe,
Though huge and in a rock of diamond armed,
Vanquished, Adramelech and Asmodai.
Id., Paradise Lost, vi. 363.