The Beadcap 11.5mm Acorn is stamped and formed from brass. The inner dimensions are 11.5mm diameter x 4.2mm depth. The outer dimensions measure 12.7mm diameter by 4.7mm depth. The hole is 1.7mm and the beadcap weighs in at .002 pounds. We plate with copper, 24k gold and .999 fine silver and then antique them to give them that aged look.