Antique Victorian dendritic moss agate gemstone and yellow metal ornate oval brooch, gorgeous green inclusions

Antique Victorian moss agate brooch, with a lovely yellow metal setting (probably gold plated but untested) and a large oval  dendritic moss agate stone with gorgeous green inclusions and a smooth shiny surface. The stone is bezel set with an open back to let the light stream through.

The brooch has a length of about 1 3/4 inches and a width of about 1.5 inches. It fastens with an antique longer length pin and old style 'C' hook clasp and is in good vintage condition. Within the moss agate stone, I have spotted on inclusion hairline crack which I have tried to show in close-up in picture 11. It is however hard to see and the surfaces above and below it are smooth so it is completely included within the gemstone.