adamantean

CIDE DICTIONARY

adamantean, a. [L. adamantēus.].

 Of adamant; hard as adamant.  Milton.  [1913 Webster]

ROGET THESAURUS

adamantean

Hardness

N hardness, rigidity, renitence, renitency, inflexibility, temper, callosity, durity, induration, petrifaction, lapidification, lapidescence, vitrification, ossification, crystallization, stone, pebble, flint, marble, rock, fossil, crag, crystal, quartz, granite, adamant, bone, cartilage, hardware, heart of oak, block, board, deal board, iron, steel, cast iron, decarbonized iron, wrought iron, nail, brick, concrete, cement, hard, rigid, stubborn, stiff, firm, starch, starched, stark, unbending, unlimber, unyielding, inflexible, tense, indurate, indurated, gritty, proof, adamant, adamantine, adamantean, concrete, stony, granitic, calculous, lithic, vitreous, horny, corneous, bony, osseous, ossific, cartilaginous, hard as a rock, stiff as buckram, stiff as a poker, stiff as starch, stiff as as board.