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.