It’s leather, it’s acrylic, it’s Marni.
Their pop-up store describes the bracelet this way: Runway bracelet in leather. Wide bracelet in different sizes. Closed by two press-studs bearing the Marni logo. Rectangular, gilded metal base on the wrist, surmounted by an acrylic resin, faceted stone with a geometric, colored square pattern.
Yours for USD $470.