Antique Victorian Button Stud Cuff Link Gray Quartz Gold Plated Square 1880s

Antique Victorian 1880s quartz button stud/ cuff link Unique square SINGLE button stud or cufflink featuring a flat gray-black quartz cabochon (possibly dendritic quartz) bezel set in a yellow gold plated square with a beveled edge Hinged closure on back (flips up to slip through the button hole and then down to secure it) *Light discoloration to metal Stamped Pat Nov 16 1880 - I've attached a patent application for the mechanism from the same year Very good antique condition Button studs were used by both men and women as a decorative alternative to buttons Measurements are approximate Length: 3/4" Width: 3/4" J4753