A carved coral hand grasps an object - a gavel? A magnifying glass? The diamond "lens" is attached to a silver handle, and I wonder whether it might be depicting a Coddington or Stanhope-type magnifier, both early handheld microscopes. They were developed in the 19th century to help get extremely close views at botanical specimens. Coral hand charms were popular in 19th-century Europe, especially in Italy, where coral had longstanding associations with protection and luck. Not every hand charm represented a specific gesture, though, and this one seems more figurative than symbolic in any obvious way. The scientific element - if that's what it is - is something I've never seen before.
MATERIALS: 18k gold (tests), silver, coral, .15ct old mine cut diamond, new 14k gold chain
AGE: c. 1880
CONDITION: Very good - minor surface wear commensurate with age and use
SIZE: 1 1/8" length including the bale, 3/4" width, 18" chain