Once in a Blue Moon

Once in a Blue Moon ... is a common way of saying not very often, once in a long time and when we say that we usually refer to something nice, special and extraordinary.
Beautiful big dangling hoops in sterling silver and blue resin, feature two blue moons, the sterling silver has been hammered to make it of a shimmering effect and the moons are in blue translucent resin.
www.etsy.com/listing/78559121/blue-moon-sterling-silver-earrings