Silver Key (The Base)
The Silver Key is a key found in Tomb Raider Chronicles in the level The Base. The key is found twice in the level. For the first time it's found in a metal locker in the same room with the mechanical claw. It's used on a locked door that leads to a stairway going upstairs.
The second time the key is found is when Lara kills a soldier in the room where a fuse is missing from a machine. The soldier drops the key, which is used to another locked door that leads to an upper platform where Lara overhears a discussion between Admiral Yarofev and Sergei Mikhailov.