|This article contains massive spoilers. If you do not wish to have your game experience spoiled, do not scroll down!|
Slade is the stone that makes up the surrounding layers of eerie caverns. After dwarves dig deep enough down into adamantine veins, large, demonic caverns made of slade will open up and spew forth demons. Curious structures are also made entirely of slade.
Slade is very, very heavy - according to the density specified in the raws (200 grams per cubic centimeter), a single half-meter diameter boulder weighs around 14 metric tons; by comparison, an equivalent volume of freshly mined platinum nuggets weighs around only 1.5 metric tons (but can somehow still be picked up by a dwarf) - making slade around 9.348 times as dense as platinum, and thus the heaviest material in the game.
In Fortress Mode, it is not possible to mine through slade walls (although a bug allows channeling through floors from above, it does not actually remove the wall underneath it), and it cannot be imported, therefore the material is completely unusable in the game itself. It is likely usable like any other stone when mined.
It is possible to use weapons made out of this extremely dense material in Arena mode - tests show that weapons and armor made out of this superdense rock are at least comparable to if not stronger than even Adamantine.
In worlds generated in version 0.31.12 and earlier, slade was incorrectly classified as both a stone and a metal, permitting nobles which liked slade to mandate the production of slade items, often leading to unfortunate accidents.
[INORGANIC:SLADE] [STATE_NAME_ADJ:ALL_SOLID:slade][DISPLAY_COLOR:0:0:1][TILE:176] [ITEM_SYMBOL:'*'] [DEEP_SURFACE] [DISPLAY_COLOR:0:0:1] [SOLID_DENSITY:200000] [IMPACT_YIELD:4000000] [IMPACT_FRACTURE:5000000] [IMPACT_STRAIN_AT_YIELD:100] [COMPRESSIVE_YIELD:4000000] [COMPRESSIVE_FRACTURE:5000000] [COMPRESSIVE_STRAIN_AT_YIELD:100] [TENSILE_YIELD:4000000] [TENSILE_FRACTURE:5000000] [TENSILE_STRAIN_AT_YIELD:100] [TORSION_YIELD:4000000] [TORSION_FRACTURE:5000000] [TORSION_STRAIN_AT_YIELD:100] [SHEAR_YIELD:4000000] [SHEAR_FRACTURE:5000000] [SHEAR_STRAIN_AT_YIELD:100] [BENDING_YIELD:4000000] [BENDING_FRACTURE:5000000] [BENDING_STRAIN_AT_YIELD:100] [MAX_EDGE:1000] no swords until you can pick mats [ITEMS_HARD] [IS_STONE] [UNDIGGABLE]