These two thimbles are examples of two kinds of enamel thimbles. They are both from China and available through The Ladies Parlor, a website with 19th-to-early-20th-century style sewing accessories and knick-knacks. The thimble on the left is cloisonné for $4.50; the one on the right is plique à jour for $7.00. I will spare you the gory details of the enamelling processes involved. Roughly speaking, in cloisonné a design is outlined in metal wire on metal background; the design is then filled in with different colors of opaque enamelling. In plique à jour, the design is outlined without the background--think of filigree--and filled in with translucent, vitreous enamelling; a stained-glass look, but a little different.
Anyway, I like the look of these thimbles sold by The Ladies Parlor because it's a little softer, more finely-detailed than I have found in cloisonné and plique à jour thimbles.