Vintage/antique filigree button, known as a Dutch blackberry type - with coiled rings surrounding a granule on top. The back is made of wired panels with figure-of-eight infill. Hollow inside and you can see daylight through the button which indicates a 19th century date. It has a loop and toggle attached to the ring shank - slight damage to the loop as shown - but button in good vintage condition. A pretty example

Size 11/16” (1.7 cm)