DIAMOND
Literally, “world-goddess”. The ancients used to believe gem stones were solidified drops of the divine essence, embedded in rocks when the world was created. Diamonds were sacred to the Mother of the gods because they “ruled” all other stones by their superior hardness.
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In the transition from tarot cards to modern playing cards, diamonds replaced the ancient suit of pentacles, which were symbols of Mother Earth (Tara) and of the feminine earth element.

Walker, Barbara G. (1986), The Women’s Encyclopaedia of Myths and Secrets, Harper & Row, San Francisco