The meaning of the ancient Greek word it originated from which means “untameable, invincible”.   Philosophers would speak about a legendary unbreakable stone, they called Adamas, or Adamant. And when the diamond was discovered, people assumed it must be the mythological Adamas stone.

Thousands of years later, in English, people began to use the word to refer to something that cannot be altered, for example, if someone is “adamant’ they are as unyielding as this mythical stone. There is something strong and mighty in that word, and the unconquerable stone that it describes. Precious, absolutely. But not delicate, not sweet.