This is very likely 'costume jewelry', but it appears to be extremely well made.
I see a fleur-de-lis, an amber stone and white enamel, all of these elements combined have a meaning... but what?
Date wise, I would guess third quarter of the 19thc.
"Amber stone is not strictly speaking a stone at all, but is fossilized resin. Through the millennium, jewelry made from it resembles gemstones, so it is sold as a gem stone. Archaeologists have found many beautifully carved amber pieces in graves, dating back around 2000bc. Amber stone artifacts and jewelry have been found in many places, and this may be because it was possibly a trade item that ended up in the hands of those who had the wealth. The meaning of amber healing attributes has been well known as it has been in use since ancient times. Part of its use may be attributed to its beauty. Those that used it and kept it on their body as jewelry ortalismans would have been aware that it helped to improve their health. Archeological finds made from this stone are well documented. This includes a well-known Amber cup that may have been made in Britain, as it was found at Hove near Brighton. Many of the artifacts made of amber had insects within them.If you look for them they are fairly easy to buy and its quite astonishing to see them clearly visible, trapped in the stone. In ancient times, the pieces containing insects were probably thought to have magical virtues, as they were carved into hunting talismans, worn to ensure safe and abundant hunting."
"The fleur-de-lis or fleur-de-lys (plural: fleurs-de-lis, or fleurs-de-lys) [pron, is a stylized lily (in French, fleur means"flower", and lis means "lily") that is used as a decorative design or motif, and many of the Catholic saints of France, particularly St. Joseph, are depicted with a lily. Since France is a historically Catholicnation, the fleur-de-lis became at one and the same time, religious, political, dynastic, artistic, emblematic, and symbolic", especially in French heraldry."