Abyssalite

Abyssalite is a naturally occurring tile material in Oxygen Not Included notable for its extremely low thermal conductivity and high-temperature interactions. It commonly forms thick veins, often surrounding hot biomes such as the Volcano, and acts as both an insulator and a catalyst for special state-change interactions (commonly called “flaking”) when other materials contact very hot Abyssalite tiles. In game code Abyssalite is named Katairite.

When a flaking event occurs, a Parent cell (the flaked tile) loses mass and spawns a Child in 5 kg chunks that is created at exactly 3 °C above the Parent’s phase-up temperature (the melting point if the Parent is solid, or the vaporization point if the Parent is a liquid). Flaking can occur each game tick (5 ticks per second), so a single cell can produce up to 25 kg/s of Child material under continuous flaking conditions. Common real-world uses for this mechanic include refining Crude Oil into Petroleum (and, if hot enough, further into Sour Gas) by dripping oil onto very hot Abyssalite, and turning Abyssalite itself into Liquid Tungsten when the tile is heated above Abyssalite’s phase-up temperature.

Flaking operates under two distinct sets of conditions depending on whether it is partial melting (solid Parent) or partial evaporation (liquid Parent):

• Partial Melting: requires a natural solid Parent tile (dupe-built tiles are not flaked), a gas Donor, and the Parent must have mass strictly greater than 5 kg. The Donor must be at least 3 °C above the Parent’s phase-up temperature while the Parent is at least 3 °C below that phase-up temperature, producing at least a 6 °C difference between Donor and Parent. The gas Donor must remain gaseous after giving off heat.
• Partial Evaporation: requires a liquid Parent with a minimum mass of 5010 g (5009.999 g fails), and the Parent liquid cannot be trapped (it must be able to be displaced). The Donor may be liquid, gas or solid (including dupe-built tiles). Adjacency is computed after tile movement; flaking can occur with the Donor effectively two tiles away if a 5 kg Child remains between them.

Temperature calculations for Donor temperature changes after flaking follow the game’s heat transfer derivations; the Child appears at the precise temperature noted above and normal conduction is then applied. These calculations can be exploited or produce unexpected heat generation in edge cases—solid flaking uses the Child’s specific heat capacity in some computations, and trapped liquid cases can reset Parent temperatures to the Donor’s new temperature, allowing large heat generation.

Abyssalite veins are typically at least two tiles thick; two-tile minimum thickness is necessary to achieve the expected insulation effect. Thinning seams risks allowing heat transfer and enabling flaking where it was not intended; it is best practice to check the Temperature Overlay when excavating Abyssalite near hot biomes.

Practical notes and uses:

• Molecular Forge recipe: 15 kg Isoresin + 80 kg Abyssalite + 5 Reed Fiber = 100 kg Insulite.
• Abyss Bugs consume Abyssalite as food.
• Abyssalite’s high-temperature phase is Liquid Tungsten (melts to liquid form at its phase-up temperature).
• Intentionally using flaking provides early Petroleum refinement without a Petroleum Boiler by dripping Crude Oil on naturally hot Abyssalite; care must be taken to avoid producing Sour Gas.
• For partial evaporation setups, surrounding the Parent with low thermal conductivity tiles (like Igneous Rock) and high specific heat capacity materials reduces heat bleed and eases flaking conditions.
• Because flaking bypasses Abyssalite’s low thermal conductivity during the instantaneous state change, it can be used to produce high-temperature products or to manipulate heat in nonstandard ways.