I think these are rather fascinating. I bought them on the 'net thinking they might be engraved, but I now believe they're molded. They do look slightly different from each other, but it seems like it must be due to the variation in either the etching process or the condition of the mold. To me the lovely lady on the left doesn't seem as happy and has a stronger jaw line...but it's probably not significant of anything.
They are 2.5 X 1.8 cm, and 1 cm deep. The sides are beveled and lightly ground - perhaps to hold glue better? The face is slightly convex. They are quite heavy for their size, and I wouldn't be surprised if they're lead glass.
In addition to the post photos, here's a link to a bigger one in Photobucket that shows the detail better:
http://i99.photobucket.com/albums/l288/krsilber/ladysquares2lg.jpgAny ideas about their origins/use? I'm guessing they were for a necklace.