These earrings can be used for formal occasions such as weddings and funerals. I purchased them at Matsuzakaya, but there is no warranty. I believe the base metal of the earrings is white gold or platinum. The earring backs are WG (white gold) and are hallmarked. They have been replaced with a type that is less likely to fall out. They are a greenish-black color and I believe they have a luster. No box or bag included.