The Lithostructure

The Lithostructure

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The Backrooms, much like baseline reality, possess a relatively predictable series of geosystems across space. This relatively typical yet distinctly anomalous series of geosystems is collectively known as The Lithostructure, which expands across most levels and regions of liminal space, usually existing between their immediate interior (i.e. the hallways of The Halls) and The Eternal Sky (referring to the infinite expanse encompassing liminal locations). This Lithostructure is not universal nor is it strictly consistent between areas, with arguments discussing its classification being constant among cryptogeological circles, but its existence is undeniable.

The main debate is whether or not the Lithostructure is a single network or, rather, a divided and distinct phenomenon that, while occurring across multiple levels, is not a homogenous structure.

While the latter would seem more obvious given the fact that certain formations as listed below have very obvious differences between each other, these formations can reoccur and have several consistent qualities regardless of which level they occupy.

These similarities can be attributed to circumstance, such as the relatively alike compositions of The Darkness and the Electrical Station, but the reports of the universal effects of Mend-Sedimen Energy (generally a misnomer but the term is too embedded in the field) suggest that the Lithostructure is something of a vast gestalt structure, with "tendrils" of rock and sediment that weave throughout the regions of liminality.

This is also supported by those who theorize that there is a strange sort of "order" among the various levels (such as Dr. Sol Almagro), a supportive framework that encompasses the entirety of liminal space. In this theory, the Lithostructure is the answer to the blank space of what exactly this framework is composed of- an incomprehensibly large configuration of stone.

Sesha Paul, UNCB Cryptogeologist

The geological formations present within this system vary greatly and are categorized into four main categories with outliers being present:

  • Basic Formations: Basic formations are fairly similar to sedimentary systems of baseline reality, and therefore are the most studied and understood geoformation within the Backrooms. These geoformations are composed largely of Limestone and Siltstone, with various other rock types being present in their composition. Basic formations are native to levels resembling natural spaces such as Neighborhood of Darkness and Cramped Caves. These systems contain a sparse amount of igneous stone types, likewise, crystalline formations such as Quartz, Carpet Fluid, and Firesalt are widely present within the bedrock of this geoformation.
  • Calcic Formations: Calcic formations are possibly the most abundant type of geoformation in the Backrooms. These formations are composed of calcium-rich rock, the most common of which being Alabaster and Limestone. Calcic formations are found on levels of the Backrooms resembling modern-day structures containing drywall as a building material such as The Office. Carpet Fluid crystal formations have been observed in calcic geoformations along with minerals such as Gypsum, Calcite, and Selenite. Enigmatic objects such as petrified wooden furniture are rare but present in these formations.
  • Metallic Formations: Mysterious in nature, metallic formations occur on levels that resemble industrial structures such as The Darkness and Electrical Station. These formations, unlike baseline reality do not posses any type of naturally occurring stone as a bedrock. Instead metallic geoformations contain assorted grades of raw ore, most commonly Iron, Nickel, and Copper as their main makeup. The unprocessed metals are extremely dense and difficult to excavate with current means. Ongoing excavations into metallic geoformations have unearthed several odd, often unnatural objects such as assorted machinery parts and rusted tools.
  • Conglomerative Formations: Found on levels of the Backrooms with rock-like industrial materials such as concrete, these geoformations are fairly un-anomalous but extremely sporadic in nature. Conglomerative formations posses a mixture of Brick, Concrete, Marble and Alabaster as their bedrock. Due to the presence of metamorphic rock many precious substances such as Gold and Platinum can be extracted. Pipes of various materials have been documented carving through Conglomerative formations, though they are oftentimes disconnected from their native pipe system entirely if one is present, holding stagnant fluids and gasses inside.

Hybrid geoformations are not uncommon, such as the Metallic-Conglomerative geoformation present throughout The Sub-Basement, and levels can often have more than one formation type present.

Exotic Elements

While most of its composition can be found within baseline geology, some elements are more exotic and limited to liminal space. The most notable materials are listed below.


Firesalt Crystal formation.

  • Firesalt Crystals: Cubic crystalline masses that bear a striking orange to red-orange color. Forming in Basic Formations, Firesalt crystals are very desirable within the Backrooms for any wanderer. When ignited the crystal reacts violently and produces an explosion, making the potential offensive capabilities of the substance immense, not to mention how effective it can be for mining charges.

Carpet Crystal formation.

  • Carpet Crystals: Crystalline formations of found within Calcic Formations, a byproduct of the flow of Carpet Fluid. The crystals are regarded as somewhat unremarkable in appearance beyond a distinct dark red tint, but sell for a high price due to their more desirable aspect, their poison. Even in a crystallized form, Carpet Crystal retains its ability to kill an unprepared Wanderer if exposed (making it a common tool of assassination), and unlike Carpet Fluid, the crystals are likely to embed and cannot be easily removed with water. Unprotected skin can be pricked by the fine points of the crystal and that exposure risks putting an unsuspecting Wanderer into critical condition. Nonetheless, the poison is by no means anomalously severe or lethal and can be cured with adequate medical attention.

Shatterrock crystal.

  • Shatterrock: A misnomer, although the cryptogeological community struggles to find a fitting classification. Some suggest it is a naturally occurring inorganic mineral, others believe it is a crystal due to its origins, but to the average wanderer it is simply "Shatterrock", a turquoise-colored crystalline material that is produced by the rapid compression of Portal Shatter within a geological formation, the high temperature and pressure causing the usually ephemeral element to become static. When crushed, it releases a large amount of Portal Shatter particles that rapidly coagulate around whatever had crushed it (or whatever it hit, assuming it was thrown), teleporting them to whichever liminal space the Shatterrock was extracted from. This makes it effective for those hoping for a quick escape, but caution should be advised as the rock can easily puncture the skin when crushed, causing deep cuts and embedding if the skin is not covered. In addition, there is no easy way to tell where the resulting Portal Shatter will send you by its appearance, as it is not unheard of for traders (or the mischievous) to sell Shatterrock that originates from Pernicious Lands as extracts of the more desirable Almond Fields. It is recommended that if you are uncertain of the rock's origin, instead use the material on the offending entity/object to remove it rather than try to use it on yourself to escape, which would both undo your progress and risks sending you somewhere inhospitable. Since Portal Shatter is endemic across the backrooms, Shatterrock is likewise found within many formation types, although it is more common within Metallic and Conglomerative formations where higher pressures are more likely to produce the rare material.
  • Denim Stone: Possibly the most unusual naturally occurring material in the calcic conglomeration of liminal space, "Denim Stone" is a vein of strong cotton fabric with a twill weave, with a texture and color reminiscent of baseline denim usually found in jeans. It is unclear as to how the material manifests within the stone, and while the fabric is extractable and useful for making clothing, the cotton may be caught in heavy machinery and potentially damage mining equipment, making it more of a nuisance. Beneath the outer layer is non-anomalous rock, typically some form of limestone.
  • Almond Ice: A byproduct of the almond aquifers often found in certain metallic formations, Almond Ice is almond water that pools in the bottom of ravines or caves systems and then freezes due to the low-temperature environment. Thanks to the minerals it collects as it travels and the pre-existing benefits of Almond Water, the cave-collected liquid is very rich in a variety of compounds that provide nutrition that is otherwise not available within the Backrooms (namely calcium, iron, zinc, and sulfur), provided it is filtered properly before drinking. It is possible for the material to have been contaminated by other exotic elements in cryptogeology.
  • Liminalloy: A blanket term used to describe a variety of non-anomalous materials (such as bronze) produced by the anomalous fusion of a variety of elements. The name is absolutely despised within the cryptogeological community as it is both a misnomer (the majority of "liminalloys" are not technically alloys whatsoever) and an egregious pun. The inclusion on this entry is only to recognize the term so embedded in the independent mining community to refer to the veins of bronze and steel produced via the superposition of their component parts.

Almond opals.

  • Almond Opal: An iridescent, fragile gemstone found within selective areas of calcic formations. The stone itself is milky in color and is formed from the settling of silica within softer materials such as Denim Stone via almond water aquifers. Besides its revered beauty almond opal is relatively unremarkable, being a close cousin of baseline opals. The main difference that separates almond opal from baseline opal is that it contains high concentrations of heavy metals and traditional building substances such as fiberglass insulation. The limited utility of this stone is as a poison to lace consumables with, as when it is crushed into a powdered form it is nearly undetectable by both scent and taste.
  • Carpet Stone: A very common rock present within calcic formations, formed from the petrification of carpet fibers. Carpet stone can vary wildly in pigmentation, but the most common colors are tan, gray, and shale blue. Because of its porous nature desperate wanderers have found carpet stone useful as an impromptu filtration method for liquids. Some wanderers also use the stone to partially remove the sickly bittersweet taste from almond water by thoroughly filtering the substance through the rock several times.

Paintstone chunk.

  • Paintstone: A concrete-like substance found within conglomerative formations that is banded with a graffiti-like pattern. Paintstone is extremely reactive to chemical changes in its environment, making it an effective tool for locating certain substances or avoiding entitles. The color of the stone's pattern will gradually shift when in the proximity of a chemical signal. Organic compounds result in warmer toned colorations and inorganic compounds provoke cooler colorations. Further study is underway to potentially use this stone for locating minerals by analyzing the slight color changes when in the presence of different materials.


Mend-Sedimen Energy actively repairs The Lithostructure, making long-term mining operations difficult to maintain, requiring constant excavation along the entirety of the shaft to prevent the tunnel's entrance from sealing and trapping those inside the tunnel. Therefore, major operations are usually sponsored or funded by a transliminal organization such as the UNCB.

  • Operation Ferron: A working body of ~60 individuals under the supervision of the UNCB. The goal of Operation Ferron is to extract large amounts of raw ore from the Metallic-Conglomerative formation of The Sub-Basement. One of the first operations of its kind- before Ferron, most mining operations were from independent groups or individual miners, making it another example of the attempted "nationalization" of various industries by high-ranking officials to decrease the UNC's reliance on imports from non-UNC organizations. However, any major refinement effort is usually entrusted to various independent groups across liminal space.
  • Project Cerberus: The Guild's answer to Operation Ferron. A Grand-Mercantile Guild operation consisting of ~20 individuals delving deep into the Calcic-Conglomerative Geoformation within Boundless Retail. The goal of Project Cerberus is the possible unearthing of theorized 'buried' sections of the level that would otherwise be inaccessible. While smaller in terms of manpower, the operation is very well-equipped and has a more skilled pool of workers. More importantly, none of its assets were purchased from member states of the UNC and were either produced by the GMG or commissioned independents.
  • Extraction Effort #12: The 12th of its kind and referred to as "Excavation Mu" by those assigned to it. While there are several other operations within Pernicious Lands, some of which are the still-functioning remains of previous "Excavation Efforts", Effort #12 is the most recent and the most organized expedition into Pernicious Lands for extraction purposes, comprised of independent groups and assisted by native tribes, who have established an outpost within a major cave system for protection from the harsh atmosphere and for easy access to raw ore, exported via elevator into the depths of Pernicious Lands that lead to Padlock Passways for transport. Partially funded by the UNCB.

Notable Examples/Exceptions

It is important to keep in mind that the Lithostructure is a general term ascribed to the majority of if not all geological formations within liminal space. A level or region that has a lithosphere of any kind would be described as possessing elements of the Lithostructure, as the Lithostructure is the lithosphere of the Backrooms and beyond.

This classification is of course controversial, with several scholars finding it too vague or even ridiculous, believing that since each level is separate from each other, the geosystems present (assuming they exist in each) must also be treated as separate and distinct geological bodies.

"If Sesha's 'Lithostructure' is so all-encompassing, so everpresent, why must its classification exist at all? If the title of 'Lithostructure' refers to all geological formations, then where is the line drawn between "extension of the Lithostructure" and simply "rock"? The trends of various sedimentary systems across liminal space are just that, trends. We have a preexisting place for the classification of these systems, and it is in the description section of a level's entry into the Archives. The term is redundant, only popularized by Vagrants- a group of which Sesha is a part- who want to further complicate and obfuscate legitimate academic endeavors with flowery language and the craving for yet another "grand and eldritch" entity to dedicate their obscene art to."
-Response to the "Lithostructure Theory" posited by Sesha Paul, authored by the late UNCB Cryptogeology Head Ekaterina Sevastopol.

The controversy over the term has led to a general reluctance to utilize the word in reference to a liminal region's geology within entries to the Archives but within academic discourse the word "Lithostructure" has found increasing relevance when used to describe the consistent trends between geological formations across liminal space. However, the majority of mining operations within UNCB territory push against the usage of the term, since if a geological region were to be classified as a level element such as the Lithostructure, that would mean these operations would have to acquire the approval of a Cryptogeologist to continue their excavation process.

The entries below are therefore solely for unique instances of or major exemptions to the presence of the Lithostructure to prevent any academic upset.

Sesha Paul, UNCB Cryptogeologist

  • The Oxygen Ocean is an obvious example of the absence of the Lithostructure within certain regions of liminal space. While some theories (namely those that suggest the Lithostructure is the "framework" of liminal space) posit that the structure may encapsulate the Oxygen Ocean, this cannot be verified.
  • Certain cryptogeologists believe that the Lithostructure should be used to describe the geology of liminal systems beyond the Backrooms, yet others suggest that separate Lithostructures exist (or rather, separate terms should exist) for each individual system. The Crimson System, for example, may possess a separate and distinct Lithostructure from that of the Middenground. Usually, when referring to the geology of different systems, it is best to avoid utilizing the term Lithostructure to describe that system's geological formations.
  • Cramped Caves is an example of a liminal region dominated by rock and stone, and while some would consider it as a clear extension of the Lithostructure, Cramped Caves's geology is classified as its "immediate interior" and therefore recorded as separate from the greater Lithostructure.

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