FAQ: Is this glass copper coated or made up of copper? This glass is made up of 100% copper. We first made the glass with copper and then engrave and antique!Why my copper glass get rusted from inside after few weeks of use? This is a natural oxidation process. Copper reacts with the oxygen and turns black but it is not hazardous and it is completely safe and normal. You can get it clean with lemon and salt water!