Three tiny real iridescent green beetles, mounted under a glass dome with a wood base. Very Victorian, or a curiosity for a modern setting too.
I took a photo before securing the dome in place with a water-soluble glue, so that if you wish to remove the dome you can by gradually moistening the base of the glass. It is hard to take photos with the reflections from the photographic lights but one's eye sees much better and compensates for such reflections in person.
13/16 inch (2.0 cm) diameter at base, 11/16 inch (1.75 cm) tall.