Around 1920: vintage shirt buttons

Two very classic black dress shirt buttons made of black glass (maybe it's onyx too) and mother-of-pearl on the back. Can be buttoned in easily and without complications.

Details

• Color: black, mother of pearl
• Diameter: approx. 0.6 cm
• Material: black glass (it may also be onyx) and mother-of-pearl
• Original case "Franz Barca, Hamburg", 1920s
• Accessory for tailcoat (white tie); the dress shirt
• Item number: NH20-17

Note: This is an antique and not a new item. Please see the details in the photos.