Vintage guilloche clip on earrings. Pink enamel roses with green leaves on a white background prong set in goldtone metal. They measure 1 1/4" x  7/8". No wear to the guilloche or the metal.
 
Guilloché is a decorative technique in which a very precise, intricate and repetitive pattern is mechanically engraved into an underlying material via engine turning, which uses a machine of the same name.