These are vintage sterling Marcella earrings.

The back of these earrings are marked “MARVELLA”, and one side of each is marked “STERLING”. According to https://www.worthpoint.com/dictionary/p/jewelry/-american/marvella-jewelry, the items that Marvella made after 1955 had a copyright symbol on them. These earrings do not have a copyright symbol on them, so I believe they were made prior to 1955. I don’t know the original cost, but I imagine a piece this old would be rather expensive, so I am listing the original cost as $100. I’ve seen similar pieces, but not exact (ranging from $20-$40). One reason I am listing the higher cost is how much research this required.