Amethyst

Belonging to the quartz family, the purple color of amethyst quickly earned it to be associated with royalty. This explains why this gems can be found among the British Crown Jewels.
The color of amethyst, evoking wine cut with water, has earned the gem an association with the god of wine Dionysus and alleged virtues against drunkenness. We will remember above all its symbolism of good luck and romantice.
Indeed, amethyst is also associated with love because Valentine of Terni, patron saint of lovers, wore one around his neck. This explains why amethyst is the birthstone of February.