And yes....I am part Irish (surprising, giving the no drinking thing, I know....I shame my ancestors!)!
A little history:
"By tradition the ring is taken to signify the wish that Love and friendship should reign supreme. The hands signify friendship, the crown loyalty, and the heart love. The ring has become popular outside Connemara since the middle of the last century - its spread being helped by the vast exodus from the West during the great Famine in 1847-49. These rings were kept as heirlooms with great pride and passed from mother to daughter. Today, the ring is worn extensively across Ireland, either on the right hand with the heart turned outwards showing that the wearer is "fancy free" or with the heart turned inwards to denote that he or she is "spoken for". The pride of place is on the left hand, with the heart turned in, indicating that the wearer is happily married and the love and friendship will last forever, the two never separated.