10K Gold Antique Victorian Boulder Opal Stick Pin - Bezel Set Stone in Engraved Setting

Dating to the either the late 1890s or early 1900s, may I offer this 10K Yellow Gold (hallmarked as pictured) stick pin featuring a nicely sized oval cab of Boulder Opal. I had never seen a Boulder Opal before so I actually thought this was a piece of chrysoprase along with some chrysocolla so it was only when I did my research that I discovered what the gemstone actually was. From a distance, the stone looks very dark blue with deep green coloring - it's only when you get close to the stone with a magnifier do you spot the opal with its tones of turquoise blue, green and the tiniest touch of pink - very neon-like flashes of color. Length of the pin is 2-3/4"; design on top measures 11/16" x 9/16". The opal cab measures 9mm x 12.5mm within the bezel. Lovely engraved bezel decorates the top and the yellow gold is so bright and shiny. An absolutely lovely piece of antique opal jewelry. (ry)