I don't mean a button for fastening clothes, I mean a metallic decoration sewn on clothes but in the same manner as a button.
We know that both
bronze age, and later nomadic steppe peoples, often
had many metal
ornaments seen on their clothes. There are Scythian grave with hundreds of small metal bits that were sewn on clothing. The so-called
scale armor bits that are tear-drop shaped, convex and have a single hole in the middle were actually decorations sewn onto clothing.
Maybe something like that.
SC