Resource Chests are chests that can be found while exploring the world map. A lot of Resource Chests can be found throughout playing and most are hidden, with few in plain sight. The hidden ones are usually under multiple layers of ground and must be revealed completely before they can be opened. During the night they are easier to see as they glow in the dark.
All Resource Chests provide Stickers and are varied in design. Once they have been opened they shrink and disappear from the world.
To dig down through layers to access chests simply double click with the right mouse button where you wish a hole to appear, this is only doable once the required card has been researched.
Shift-D and Shift-A will rotate the camera, allowing you to search on the sides of mountains easier.