Painted button?

This is one of several buttons I rummaged out of my grandmothers sewing stuff, and am hoping to find out anything about it.

It's orange glass, and when looking at the image under magnification, it is not made of dots. I'm unsure of whether it was painted or printed in some other manner.

I took the picture on a standard size (not laptop sized) keyboard, to give an idea of scale.

The hole one the back is not glass, but embedded metal.