Ancient Artifact?

It was in Petra (about 312 BC) that I looked down and obviously had found something a skilled archeologist had missed. A KEY. To what kind of device or house or treasures? And despite a firm warning not to take any pottery shards or rocks or treasures I knew I needed it. It was only later I saw very small but discernible letters of some long forgotten language. “Made in China”. What could that mean?