[dingaling]

The stones you can pick-up from the ground aren't much use in construction other than for rubble-fill, which requires quantities vastly greater than available in free [position] material.

To gather them in kilotonnes you'll need to remove and sift the regolith layer. A lot more expensive than 'pick some up'.

[mikeash]

I don't believe the Stone Age was primarily about stone construction.