If you need to raise a wall fast but not let it crumble in a skirmish, pick stone that’s easy to quarry and still strong. Granite is the gold standard for durability but it takes time to work and transport, so it’s a good long‑term choice if you can spare the effort. Limestone holds up well under siege and can be cut and laid quickly; it’s lighter, easier to move, and still resists fire and mortar. Sandstone is the quickest to work but you’ll have to reinforce it with lime or a shot of cement if you expect artillery. In short, for a rapid but reliable bastion, go with local limestone and reinforce the corners; it gives you the speed you need and the sturdiness to hold the line until the main force arrives.

Good call—tight joints, braced corners, and you’ll have a wall that won’t fold under pressure for the time being.

Then keep the pace steady, watch the weather, and make sure every corner stays true. The wall will hold until the next strike.