Stone

Stone is a common type of raw material with plenty of uses.

Mining
Worlds normally have at least one big stone mountain, from where dwarfs can extract this resource by mining its blocks.
 * Mountain

On all worlds, excepting the Underground World, stone can be acquired by destroying the graves in graveyards.
 * Graveyards

Random nodes of five to ten stones can be found in worlds and biomes on all layers, from the surface to the magmatic earth level (diagram on the right: 1st–5th earth layers).
 * Random nodes

Crypts are the true stone mines. Some, occupied by a guardian, are harder to access without major risks or high technology. But others, guarded by a beholder, a golem and/or an ancient gargoyle along with the zombie/skeleton doors, these can be accessed on quite early game, making stone no longer scarce for no matter what purpose to the rest of the current level. Each wall block in these rooms, for example, drop five stones when mined.
 * Crypts

Disassembling
Stone can be acquired when disassembling the following items:

Walls
Stone is the best raw material for making walls and enclosing a shelter.

Leaves can grow on background stone walls, reducing the house comfort. Also slugs can appear and grow to an annoying amount. To avoid this, place torches or other sources of light.

Crafting
Stone is needed to craft:

Two stones are also required to craft each portal part in the Campaign.

Task
Ten stones are required to accomplish the task "Collect stones".