There are two types of rocks which can be found.

Large Mineral Rock

Metal Ore, Sulfur Ore, and Stones can be gathered from a Large Mineral Rock using any tool, each swing will produce 2-4 Metal Ore, some Sulfur Ore, and 4 Stones.

If you are using a pickaxe, each swing will yield more resources and you will need no more than 3-4 swings to collect the entire rock.

Small Mineral Rock

Metal Ore, Sulfur Ore, and Stones can also be gathered from smaller mineral rocks dotted around the map, but in smaller quantities compared to the Large Mineral Rock. Usually 3-7 more Sulfur Ore and 4 Stones are found in these rocks.

Using a pickaxe the same rules count as with the Large Mineral Rock - 3-4 swings to collect the entire rock, therefore also giving you much more material per hit.