Bible Dictionaries
Adamant

Watson's Biblical & Theological Dictionary

שמיר , ‘Αδαμας , Sir_16:16 . A stone of impenetrable hardness. Sometimes this name is given to the diamond; and so it is rendered, Jeremiah 17:1 . But the Hebrew word rather means a very hard kind of stone, probably the smiris, which was also used for cutting, engraving, and polishing other hard stones and crystals. The word occurs also in Ezekiel 3:9 , and Zechariah 7:12 . In the former place the Lord says to the Prophet, "I have made thy forehead as an adamant, firmer than a rock; that is, endued thee with undaunted courage. In the latter, the hearts of wicked men are declared to be as adamant; neither broken by the threatenings and judgments of God, nor penetrated by his promises, invitations, and mercies. See DIAMOND .

Bibliography Information
Watson, Richard. Entry for 'Adamant'. Richard Watson's Biblical & Theological Dictionary. https://www.studylight.org/​dictionaries/​eng/​wtd/​a/adamant.html. 1831-2.