Stone
Laterite
Iron-rich tropical soil that cuts soft from the ground and hardens in air into a rust-red porous stone. Quarried in blocks like giant bricks.
How it behaves
Porous, so it dampens heat and moisture swings in humid coastal climates; its roughness keys plaster beautifully. Weak in tension, strong enough in compression for load-bearing walls.
Where it belongs
Kerala and coastal Karnataka · Goa · Southeast Asia (Angkor's foundations)
In a modern project
Exposed laterite masonry for warm-humid houses; blocks laid rat-trap style to add an insulating cavity.