Obsidian

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Obsidian

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Graphic
Uses
Masonry Stone crafting Construction
Properties
Igneous extrusive layer Material value 3☼ Fire-safe Magma-safe Melting point 13600 °U (m) Boiling point 16000 °U (m) Ignition point none (m) Solid density 2650 kg/m³ Specific heat 800 J/kg·K Color black
Contains
All minerals common to igneous extrusive layers
Wikipedia article

v50.15 · v0.47.05 This article is about the current version of DF. Note that some content may still need to be updated. More Info · V

This article or section contains minor spoilers. You may want to avoid reading it.

For the month, see Calendar.

Obsidian is one of the types of "stone" (technically volcanic glass) that forms entire layers. Obsidian is also found surrounding magma pools and volcanoes, exactly 1 tile thick, and has the distinction of being the only stone that can be created during play. Obsidian is considered an economic stone by default; in order to allow general use at workshops, and in architecture, you must enable "obsidian" in the labor menu under 'stone use' => 'economic stone'. It is also notable in that it has the highest material value among non-ore stones and is also higher in value than some low-value ores like native copper.

"Obsidian" is also the twelfth month of the dwarven calendar, covering late Winter.

Rock short sword

Obsidian can also be made into obsidian short swords with one log at the craftsdwarf's workshop. If you embark on an obsidian mountain or manage to reach magma before finding metallic ores, these are good at first to defend your fort from early wolf and giant eagle attacks, but weak in comparison to any metal weaponry, being unable to defeat even basic copper armor, so keep that in mind once you start encountering metal-armored invaders. Note that as obsidian short swords use wood (used in the handle), elves will be offended if you trade obsidian swords, and refuse the trade.

Obsidian is the only rock that can be used to make stone-based weapons.

Previous versions lacked defined yield and shear values and used the defaults from the stone template; this rendered them very blunt and unable to cut skin. Since 40.05 obsidian features more proper yield and shear values, making these weapons much more viable. Obsidian now has glass-like yield and shear values, which allow rock short swords to slice through skin, leather armor, and wood armor used by elves.

Interestingly, Obsidian short swords in the Premium version look completely different depending on who is using them, with dwarves getting a less-Aztec-looking sprite than everyone else; not that you'd notice in gameplay, unless a kobold gets particularly lucky.

Obsidian formation

Obsidian can be formed by mixing water and magma. Any tiles containing both water and magma, except tiles also containing a magma flow, will be replaced with unmined obsidian, generating abundant amounts of steam. Tiles on a magma flow will instead replace the water and magma with just steam. When dumping water via a pond zone onto magma, the water has to fall free for at least one z-level (i.e. the pond zone must be two or more z-levels above the magma); otherwise only steam will be produced. The formation of obsidian will not affect the light level.

Most non-magma-safe objects that were in the magma prior to the formation of obsidian are completely destroyed, which can be an effective method of removing unwanted items or enemies, although long exposure times to magma are suggested to ensure destruction. All magma-safe items will be entombed in the tile, and can be regained by mining it along with any magma-unsafe items that happened to survive the casting process. No instances of globs of molten metal surviving obsidian formation have been noted, though apparently burning objects can remain on fire when cast in obsidian. The survival rate of magma-unsafe items is believed to depend on the exposure time to magma being short enough to not cause the item in question to melt or burn before obsidian formation occurs—fragile items placed in water that is then exposed to magma tend to survive casting unscathed. Creatures cast in obsidian die, even without significant exposure to magma. Creatures in cages will survive the casting process, though they may still die from exposure to the extreme temperature of magma.

Obsidian farming can be used to produce large amounts of obsidian for masonry, crafting, or construction.

Suspicious Rock Formations

Recently, strange formations of obsidian have been observed within the caverns. Shallow cavern layers will often feature 3x3 squares of (warm or damp) obsidian, while deeper layers may sometimes feature large clusters of obsidian. In all cases these formations are composed solely of obsidian and studded with many high-value gems such as emerald, diamond, star ruby, and star sapphire. Exploratory miners have reported many fun things contained within the gem-studded obsidian, such as magma, spontaneous explosions, divine artifacts, forgotten beasts, and other things. The full extent of new content is still being determined. Some scholars theorize that the precious gems were set as bait for careless dwarves who dig too greedily and too deeply.

Real life

A common misconception is that the dark color of obsidian indicates an inclusion of metals like iron. In fact, obsidian is almost entirely quartz, just at a microcrystalline level. As there has yet to be any known threat by dragon or animated frost wights, the historical use of obsidian was mostly decorative until several peoples discovered its use as a sharp tool and eventually weaponized. Localized variants like "snowflake obsidian" and "chocolate" obsidian (with brown inclusions) are typically attributed to inclusionary quartz crystals and mafic minerals, respectively.

The use of obsidian to create short swords in Dwarf Fortress is almost certainly inspired by the macuahuitl, a sword-club used by the Aztecs and the other native peoples of Mesoamerica. The weapon was a short, strong wooden staff (normally one-handed, but two-handed versions existed), set with obsidian-flake blades that were literally more than razor-sharp. Flaked obsidian can have a monomolecular edge; today, it's used for extremely high-quality surgical scalpels, which have to be handled with extreme care – a little pressure is enough for such a scalpel to cut deep, and if you cut yourself with one, you won't feel it until you start to bleed. The main disadvantage, however (other than the expense incurred from the labor to hand-knap high-quality blades), is that obsidian is quite brittle compared to metal (and alternative materials like chert or flint) – this can be mitigated to a degree through quality craftsmanship and skillful use, but there remains the risk that an obsidian blade will leave tiny but incredibly sharp glass flakes behind in the surgical wound.

Macuahuitls could penetrate flesh and leather with ease; Spanish conquistadors reported one case where a blow from a two-handed macuahuitl decapitated a horse. But the obsidian edges shattered when they struck metal armor, and macuahuitls didn't have a thrusting attack. The Spanish soon learned to put their armored soldiers forward, to fight in chokepoints – and to recruit the Aztecs' enemies, to field macuahuitl-wielders of their own (and let them do more of the dying in their place).

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  Obsidian

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  Obsidian rock face

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  Obsidian blade

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  Snowflake obsidian & an obsidian arrowhead

This article or section has been rated D for Dwarf. It may include witty humour, not-so-witty humour, bad humour, in-jokes, pop culture references, and references to the Bay12 forums. Don't believe everything you read, and if you miss some of the references, don't worry. It was inevitable.

Despite what other popular forms of media may perpetuate, obsidian – even when crafted into blocks – will not provide any assistance in reaching the underworld. The only method of reaching the underworld known to dwarfkind is to physically dig down deep enough to get there.

All claims that obsidian can be combined with blue diamonds to magically improve weapons and armor have been shut down by extensive Dwarven science.

Raws

[INORGANIC:OBSIDIAN] [USE_MATERIAL_TEMPLATE:STONE_TEMPLATE] [MELTING_POINT:13600] [BOILING_POINT:16000] [IMPACT_YIELD:1000000] from glass [IMPACT_FRACTURE:1000000] [IMPACT_STRAIN_AT_YIELD:2222] [COMPRESSIVE_YIELD:1000000] [COMPRESSIVE_FRACTURE:1000000] [COMPRESSIVE_STRAIN_AT_YIELD:2222] [TENSILE_YIELD:35000] [TENSILE_FRACTURE:35000] [TENSILE_STRAIN_AT_YIELD:114] [TORSION_YIELD:35000] [TORSION_FRACTURE:35000] [TORSION_STRAIN_AT_YIELD:114] [SHEAR_YIELD:35000] [SHEAR_FRACTURE:35000] [SHEAR_STRAIN_AT_YIELD:114] shear modulus 30.7 GPa [BENDING_YIELD:35000] [BENDING_FRACTURE:35000] [BENDING_STRAIN_AT_YIELD:114] [STATE_NAME_ADJ:ALL_SOLID:obsidian][DISPLAY_COLOR:0:7:1][TILE:177][LAVA] [MAX_EDGE:20000] [IGNEOUS_EXTRUSIVE] [MATERIAL_VALUE:3] [IS_STONE] MELTING_POINT:11818 <-- I think this is from the data collected by the contributors above and is more accurate than the numbers we're using, but we're using a high melting point until environmental lava effects are further along. [SOLID_DENSITY:2650] [STATE_COLOR:ALL_SOLID:BLACK]

V · T · E Stones
Sedimentary	Calcite · Chalk · Chert · Claystone · Conglomerate · Dolomite · Limestone · Mudstone · Rock salt · Sandstone · Shale · Siltstone
Igneous	Intrusive Diorite · Gabbro · Granite Extrusive Andesite · Basalt · Dacite · Obsidian · Rhyolite
Metamorphic	Gneiss · Marble  · Phyllite · Quartzite · Schist · Slate
Ore	Adamantine, raw · Aluminum, native · Bismuthinite · Cassiterite · Copper, native · Galena · Garnierite · Gold, native · Hematite · Horn silver · Limonite · Magnetite · Malachite · Platinum, native · Silver, native · Sphalerite · Tetrahedrite
Economic	Alabaster · Bituminous coal · Calcite · Gypsum · Kaolinite · Lignite · Satinspar · Selenite
Other	Alunite · Anhydrite · Bauxite · Borax · Brimstone · Chromite · Cinnabar · Cobaltite · Cryolite · Graphite · Hornblende · Ilmenite · Jet · Kimberlite · Marcasite · Mica · Microcline · Olivine · Orpiment · Orthoclase · Periclase · Petrified wood · Pitchblende · Puddingstone · Pyrolusite · Realgar · Rutile · Saltpeter · Serpentine · Slade · Stibnite · Sylvite · Talc