Copper buried chests with an item to make telescopes more interesting

Buried treasure chests would have 10% chance of being made out of copper. To open a copper chest you need a captain's key, which is found rarely on shipwrecks (only on the chest that has paper, books, etc). The loot is similar to a normal buried chest, with a few differences:

- More chance of having diamonds

- Chance of having a nautilus shell

- Little chance of having a turtle scute

- 100% chance of having telescopic lens, an exclusive item which combined with a telescope on a smithing table creates an adjustable telescope (i'm not sure about the name)

With the adjustable telescope, you can adjust the zoom while using it, going from 50% of the normal telescope zoom to 200%.