Mase

The Rock Cracker mutation is arguably pretty useless as it is right now because it essentialy just saves you a few seconds when hammering down on a resource node. On the other hand the need for quartzite, mint and candy escalates enormously in the later stages of the game especially if you play with friends. Even upgrading your weapons to level 7 takes ages with more people and grinding for the required resources just bogs down the otherwise very fun experience. If the Rock Cracker mutation would give you 1-3 extra resources depending on the level of the muation and the type of ore you are mining it would help to counter this problem at least a little. It would also not change the balance at the beginning of the game since you would need to crack a lot of rocks in the first place before getting the mutation. Later on though when the need for quartzite etc. increases you could use the muation to mitigate this.