Bottoni in vetro ceco vintage

It’s more of a decoration than a button with a practical use. This type is typically used in jewellery. Or you can add it to clothes, hats as a sort of permanent brooch. I guess they could be used as fasteners like normal buttons, but I haven’t really seen it. My grandmother sews them onto ribbons for her hats, or adds them to necklaces. She has one such button in two versions, one is on her hat, and one is sown onto a belt.