The distinctive Irish claddagh ring is believed to have originated from 𝙘𝙡𝙖𝙙𝙙𝙖𝙜𝙝 (the shore) near Galway, circa 17th century. It represents love, loyalty, and friendship. A married woman wears the ring on her left hand with the heart facing inward. A single woman wears it on her right hand with the heart facing outward. While the ring is assocaited with weddings, it can also be given in friendship.
Fun Fact: Although the story in Through the Veneer of Time takes place in the 16th century, I couldn't resist weaving a very special claddagh ring into my plot. Unsurprisingly, one reader caught it right away — I knew someone would! Oh well, call it creative license ;)