Shabbos, Chapter 6, Mishnah 6. The Mishnah lists a number of items that a person may go out with on Shabbos, even though they are not ordinarily considered jewelry or ornaments.
"Hayotzei b'sela shebbal hamakah" - One who goes out with a sela coin over a wound:
A person is permitted to go out on Shabbos with a coin - a sela - resting on top of a wound. This wound is located on the sole of the foot, which is a particularly bad place for a wound or a sore, because it is very difficult for it to heal there. In order to protect the wound from getting worse, people would tie a coin over it, which would shield it and allow it to heal, and therefore one may go out with it on Shabbos.
"Habanos haketanos" - The young girls:
The Mishnah continues and says that the young girls, meaning little children, may go out with threads and even with small pieces of wood in their ears. Their ears would be pierced, and they were too young to wear earrings made of precious metal; so in order to keep the holes open, people would insert a thread or a small piece of wood, something like a splinter. Even though this is not jewelry or an ornament in the way we usually think of one, they are permitted to go out with it on Shabbos.
"Arviyos u'Madiyos" - Arabian and Median women:
The Mishnah now turns to speak about two different nationalities. The Arabian women - and this does not mean Arab women, but Jewish women who live in Arabian regions - go out with their heads and faces covered, something like today's burka. They may go out wrapped in this fashion, and it is not considered a load or a burden that is being carried.
And those women from a country called Media go out perufos. "Perifah" is a method of fastening a garment, a shirt or a dress:
At one end there was a strap, which served the function of a buttonhole.
And at the other end of the garment they would tie a small stone or a nut in its shell, and this served as a button, to make sure the garment would not fall off.
"Ella shedibru chachamim bahoveh" - But the Sages spoke of the present situation:
The Mishnah concludes by noting that any person may go out in a garment of this sort, whether wrapped like a burka or fastened with a button. The fact that the Sages attributed this specifically to Arabian and Median women is only because that is how it was commonly found: the Sages spoke of the present situation, of the practices that were accepted in those parts of the world. That was the place where women were accustomed to wrap themselves, and in other regions they were accustomed to use the method of perifah. But any woman is permitted to go out this way on Shabbos.