The copper finish findings on this page are cast, stamped or formed from brass and then receive a durable Antique Copper colored finish. You'll find that the price per piece on these items is usually much lower than a similar item made from solid copper.
There is some information that you may want to know about the cast finding manufacturing process. Casting allows for rather intricate patterns on the surface of the parts. Since the pieces are made from molten metal that is forced into molds, you will see some variation in some of the pieces due to how much material was injected into each space in the mold. While most beads will be rather uniform, this means that you will see occasional parts with "bumps" at the edge (too much metal) or places that don't look quite filled out (too little metal). Small bumps or knobs on an edge can be snipped off with a wire cutter or smoothed with a metal file, as brass is a fairly soft material (like copper or silver). The underlying brass material is very similar in color to the antique copper finish, so even if you file an edge or if the finish wears down over time, it is not going to very noticeable. Occasionally, we also have items cast from base metal (rather than brass). Those items will be clearly marked within the detailed description.