The quantity of resource gathered by each strike is equal to the Harvesting Power of the tool, with a 50% chance of gaining an additional resource. Resources are gathered by striking an object in the world with an appropriate tool.
Other resources can be significantly harder to locate, such as Silverstone, Obsidian, and Star Metal Ore.
Some resources, such as Wood and Stone are easy to find - just hit a tree or large boulder respectively with a harvesting tool. 2.1 Tool Categories - use the correct tool.