Many stores sell copper vessels which are manufactured with a mix of other metals. Those copper bottles are not pure and imitate. Here are some tricks to identify pure copper.
Copper does not have magnetic properties, hence it would not get attracted towards any magnet.
Squeeze a lemon and rub around. Put some salt and water inside the bottle, close the lid and shake well. Rinse. The Bottle will give pinkish-red glow if it is pure copper.