You can make infinite source of cobblestone making a cobblestone generator. Follow the simple steps below

Read the “Things you will need” section

Make 2 4-block high pillars 1 block away from each other

Put a circle around it

Dig a 2-block wide hole, leaving the 2nd space 2 blocks down from the left side pillar

Put a water source on the left-most side of the hole

Dig 3 holes like this:

• Put a lava source in the middle of the circle we made in the 3rd step
• Destroy the block in the middle of the water- and lava-flows

Note

• Make sure that cobblestone appears replacing the block.
• You should do this around your spawn point in case of an accident, unless you are using an infinite health hack or are using diamond armor in decent condition.

• Be careful around the lava.