M melaniesmelanie Curious May 31, 2020 #1 May 31, 2020 #1 Yelloooooo!!! I recently purchased a lovely used ring from a market containing marcasite and amethyst. On the inside is the usual 925 for silver, but it also has 101f0 stamped. I can't find it, does anyone know what it means, who it belongs to? Thanking you!