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Silicon-Based Life

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It's silicon-based, lives in molten lava, and makes ear-splitting dolphin-shrieks capable of piercing even the void of space. Not all alien races can be cute or sexy.

Zyzyx: Now, Grakkus there is none too quick on his feet. It's probably because he leads such a... sedimentary life.
Eldred: ...Never do that again.

Sometimes in science fiction, you'll find aliens whose bodies replace carbon with silicon. In hard science fiction, the plausibility of this trope rests on carbon and silicon being in the same family of elements: the ability to form four bonds opens the door to a vast array of potential complex nanostructures.

Silicon biochemistry would be wildly different though: you can't replace carbon with silicon in known biomolecules and get anything functional. Even the small "hydrosilicon" molecules are much more reactive than their carbon counterparts. Plus, carbon is actually not so common on the earth, with the SECOND most abundant element being... wait for it... silicon.note  If that kind of life were able to form, it's reasonable to assume it would have done so here (as you know, it didn't).

It's somewhat more chemically plausible to base life on silicates (silicon oxides), which have a huge variety in nature. These species would either have to exist at molten-glass temperatures, or be very slow (literally geological). Silicate based lifeforms would definitely be more Starfish Aliens than Rubber-Forehead Aliens.

In the Media, Silicon-based aliens tend to come in one of three flavors:

  • Rock Monster: The organism at first glance looks like an animate mass of rocks, crystal or the like. This exterior may hide an inner system as complex and intricate as your own insides, or it may be mineral through and through like the Golems and elementals of fantasy (which are sometimes examples themselves, when they're specifically made out of silicate rocks or minerals). The scientifically accurate version described above would technically be a case of the former, albeit much hotter to the touch or slower-moving than most fictional examples.

  • Mechanical Lifeform: As the name suggests, you're dealing with a planet of Robots and Machines here. They might've been built at some point in the past, or evolved naturally. Note however that while Mechanical Lifeforms are potentially plausible, calling them "silicon based" would be incorrect; while computers do use a lot of silicon at the current technological stage, they aren't silicon-based in the same sense that Earth life is carbon-based. They aren't anything-based, as there are no internal chemical processes in the first place. Furthermore, silicon isn't even absolutely necessary for the building of a computer in the first place; any material that can be used to make a wire will do, it's just that Silicon is the most practical material to use.

  • Miscellaneous: The rarest type. These "Siliconers," if you will, are weird in some other way, or perhaps even par for the course when compared with all the other carbon-based aliens in the setting. At the very minimum they will likely still be unable to eat the same food as humans (averting No Biochemical Barriers in the process), even if everything else in the setting can.

Most of the examples below are not hard science fiction. Authors have a lot of fun with the possibilities. Sometimes other elements are used, which don't have to be in Group 4 of the periodic table.

For some reason, a siliconer is very likely to be a Starfish Alien, even if they're the sole example in a sea of Human Aliens and Rubber Foreheads, despite those tropes being equally implausible regardless of chemical composition.

Even when a setting has Loads and Loads of Races, there isn't likely to be more than one planet of Siliconers, their biochemistry likely being one of their defining characteristics.

See also: Living Statue, Golem, Rock Monster, Crystalline Creature, Sentient Sands and Body to Jewel.


Other Elements


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    Anime and Manga 
  • The Tekkamen from Tekkaman Blade look like they are simply wearing Powered Armor after their Transformation Sequence, but it's explained in-series that they are actually transmuted into crystalline-based entities.
  • Haruhi Suzumiya: Silicon-based Data lifeforms were responsible for the mysterious happenings in one of the two stories of the eighth volume. But they live on without their bodies. How? That's classified, apparently.
  • Blame! features a race called the "Silicon Creatures" or "Silicon Lives". Like the rest of the cast, they're actually just advanced cyborgs who "evolved" from humans, but they're so heavily altered that it's hard to say if the fleshy-looking parts of them are really flesh or not anymore.
  • In Gundam 00 Awakening Of The Trailblazer, the Extraterrestrial Living metal Shape shifter is hinted to be this... for a series that never had aliens, they are supposed to be the Mecha-Mooks of the story.
  • In Project ARMS, the alien life form Azreal is silicon-based. The discovery of it is what gets the Egrigori to kick-start their various ARMS experiments. It also saves the day at the end, when it's revealed that Azreal is nearly immortal because of its silicon makeup, which leaves it very lonely and more willing to sympathize with the protagonists than Keith White (who wants to kill everyone on Earth and essentially condemn Azreal to an eternity alone).
  • JoJo's Bizarre Adventure: JoJolion introduces rock humans (and later, rock animals), human-like beings that hibernate for months at a time by turning into stone. Urban Guerilla, a member of this species, claims that the equivalent exchange feature of the rokakaka fruit has "low compatibility" with carbon-based life forms, since it was cultivated for and by the rock humans, who are silicon-based life forms.

    Comic Books 
  • Green Lantern:
    • Rot Lop Fan, from Tales of the Green Lantern Corps Annual # 3, is stated to be a silicon-based life form in a galaxy with no visual light spectrum. He looks like a frog.
    • In another story by Alan Moore collected in the same book, there is a rare example of a more realistic portrayal of silicon lives as they would exist at Earth-like temperatures. When their planet is invaded by the power-hungry Spider Guild, the silicon beings, resembling giant stone statues of men, don't even notice because they move at a geologic pace.
  • Blok from Legion of Super-Heroes, as well as Strata from its sister title, L.E.G.I.O.N.
  • Stonians, from Astonishing Tales #22 and Strange Tales #74, are silicon-based lifeforms.
  • Superman:
    • Superboy (Kal-El) had to save a race of silicon-based aliens called the Vulxans in The New Adventures of Superboy #7 (1980).
    • "Strata" and her family from Superboy and the Ravers are silicon-based aliens.
    • In The Killers of Krypton, the bodies of the Trilium alien species are made of some crystalline, blue organic mineral.
    • In The Untold Story of Argo City, Supergirl and her biological parents stop an invasion from an alien species whose bodies are made from liquid fire.
  • Doctor Who Expanded Universe: In "Under the Volcano", a comic story published in Doctor Who Adventures Magazine, the Doctor and Rose run into a silicon-based species called the Chalderans.
  • Babe and his race of people from Atari Force, who grow to become literally mountains as they get older.
  • Martinex of the original Guardians of the Galaxy, a transhuman alien from the Human Subspecies that was engineered to live on Pluto. He basically looks like a human-shaped diamond; apparently this helped him live comfortably under Pluto's harsh climate.
  • Marvel's most frequently seen silicon-based aliens are the Kronans, introduced in the very first adventure of The Mighty Thor as the "Stone Men From Saturn," though it was later established that they'd only maintained a temporary base there. The Incredible Hulk's buddy Korg is their most well-known representative.
  • Wonder Woman Vol 1: In the Silver Age Diana once fought a time traveling crystalline alien that had disguised itself as a human under the name Professor Andro. Whatever he is made of is very resistant to blunt force damage, but he instantly shatters and dies when struck by lightning.
  • An issue of Marvel's S.W.O.R.D. had rock aliens going on a rampage because they mistook Mt. Rushmore for a Dead Guy on Display. They obviously have rocks for brains but quickly make amends once it's explained to them.

    Fan Works 
  • Stargate Atlantis: In the Dark Frontier fanfiction, the Shade are a strange hybrid of carbon- and silicon-based life: they are mostly carbon-based but use a powerful acid to digest any mineral in order to build and repair a silicon-based exoskeleton. Their unusual composition also gives them the ability to use ammonia and sulfuric acid for what we use water. Oh, and they are cold-blooded, capable of draining anything from alkaline batteries to energy shields in order to stay alive for months without feeding in any environment. The biggest ones (few thousand miles across) strip mine entire planets for naquadah and trinium, also draining the planetary core for heat; when they move on, the planet is essentially a dead husk locked in an eternal ice age while the metals are used to build planetoids which serve as hatcheries. Despite being living creatures, they are apparently capable of entering hyperspace.
  • All the World's a Stage has the Ania as such, being described as made of glass. Alex Rand says they're microorganisms taking form upon contact with any solids, both crystalline and amorphous. He also describes then as dangerous predators, able to rip apart anyone in mere seconds. By the way they're described and how they act, they bear a strong resemblance to the Broken Glass Creature from a Touch of Glass, a Creepypasta.

    Film — Live-Action 
  • Xenomorphs from the Alien franchise are apparently silicon based. This is possibly the reason why their highly corrosive blood can eat through a ship's hull but not themselves.
  • Gorignak from Galaxy Quest.
  • Lost in Space features silicon-based spider-like lifeforms.
  • The Silicates in Island of Terror.
  • The giant space slug in Star Wars V , which is officially called an exogorth, is silicon-based, as are the winged creatures inside it, which are called mynocks. This detail is not mentioned in the film and comes from the Expanded Universe.
  • Gamera 2: Advent of Legion features the titular Legion, whose primary threat actually comes from the fact that she’s silicon based. However, the fact that she’s based on silicon winds up making her less resilient than her fleshier carbon based foes.
  • The titular Smog Monster from Godzilla vs. Hedorah is mentioned in passing to be an alien mineral-based lifeform, comprised of a form of crystallized carbon that bonds with waste particles and fluids to become an animate sludge.
  • The titular character in The Magic Crystal, although due to budget limitations and lacking in the special effects department, the crystal is portrayed by a hollow plastic chunk with a green bulb inside which glows as it communicates with humans.
  • Max Steel has Steel, a techno-organic life forms that feeds off energy, made of silicon. Another way to say it is an alien robot.
  • In the novelization of Pacific Rim, it’s mentioned several times that the Kaiju are silicon-based. It’s worth noting that the novelization was based on an earlier draft of the script, and that this is not mentioned in the film proper, the sequel, or the anime spin-off, with the film proper implying that the kaiju are ammonia-based.
  • Korg the Kronan from The Incredible Hulk made his big screen debut in Thor: Ragnarok.
  • The Monolith Monsters were silicon-based.

  • Sentenced to Prism, a Humanx Commonwealth novel by Alan Dean Foster. Most life on Prism is silicon based. Foster has a lot of fun with the possibilities: natural Frickin' Laser Beams , rich colouration, lots of armour, a casual approach to being on land or underwater (the inhabitants consider water 'thick air') and so forth.
  • The Isaac Asimov short story "The Talking Stone" was about Silicon-Based Life forms called "siliconies" that lived on asteroids. They survive by absorbing gamma rays from radioactive ores.
  • Stanley G. Weinbaum's short story "A Martian Odyssey" had a silicon-based life form that consumed silicon and excreted silicon dioxide bricks.
  • Discworld: Played for laughs, but Trolls qualify. It is specifically noted that, as silicon-based organisms, they function like supercomputers, with processing speed (and thus intelligence) being inversely proportional to temperature. One of them uses Hulk Speak at room temperatures, but when locked in a freezer for a while, almost came up with a unified field theory. They also count in either base four or binary because of that.
  • The third Young Wizards book has a planet of silicon-based life forms, the fact of which ends up being extremely important. As it turns out, they can function like extremely complex computers.
    • Later books mention in passing that to some silicon-based species, chocolate is an aphrodisiac.
  • The Dancing Meteorite by Anne Mason includes a flashback to humans' first encounter with silicon-based life, which the human explorers think is just part of the landscape until it rises up and attacks them.
  • Ullerans in H. Beam Piper's Uller Uprising. The concept is made more believable by using siloxanes (alternating silicon-oxygen chains), some of which are pliable at what we consider room temperature. Piper didn't come up with idea - he was presented with an introductory essay by Dr. John D. Clark describing life on both Uller and Niflheim (see entry below under "Other Elements".
  • Dark Is The Sun by Philip José Farmer: Phremompit is a silicon based lifeform native to an asteroid, coming to Earth in a meteor shower. He eats radioactive rocks and moves on natural treads. Unfortunately, he drills through many people before learning his morse-code communication laser is turned up a bit too strong for the mushy-bodied earthlings.
  • In Ben Bova's Venus, it's discovered that such a lifeform inhabits the titular planet. It has a massive underground body, and tentacles a few kilometers long which it uses to search the planet's surface, for food or whatnot.
  • The vampiric beings from The Stress of Her Regard and Hide Me Among the Graves appear to be this trope, although it's slightly too early in history for the characters to describe them in terms of modern chemistry.
  • In Michael Flynn's The January Dancer, the prehumans.
  • In "Jimsy and the Monsters," a short story by Walt Sheldon, a scientist uses teleportation to bring two silicon based organisms to Earth.
  • Starfleet Corps of Engineers: The planet Sarindar has a silicon-based biosphere.
  • The Laundry Files: There are creatures living in the Earth's mantle — codeword DEEP SEVEN, or "Cthonians". True to the more realistic version of this trope, they freeze to death at any temperature where rock is a solid. True to the general tone of the Laundry Files, they're massively more technologically advanced and numerous than us, have insanely powerful war drones that are fully capable of coming up to the surface to squash us, and may realize any day now that they have very good reason to want us squashed.note 
  • The Osmerian Conflict: One of the alien species are the Silicians. As their name suggests, the major element in their bodies is silicon in the form of silicates.
  • Star Wars Legends: The Wildlife of Star Wars describes silica parasites, such as granite slugs, shadow barnacles and duracrete worms, which are a group of inveterate animals with silicon-based biology and can feed directly on silicate minerals. This makes them a serious issue on the City Planet of Coruscant, where their feeding on building materials causes a great deal of damage to buildings. Notably, the carbon-based hawk-bats can subsist with no issue on a diet consisting primarily of granite slugs.

    Live-Action TV 

    Multiple Media 
  • The titular Transformers are this; despite resembling (giant) metal robots that can transform into different objects (hence the name), they're surprisingly enough shown to be quite similar to organic life, such as having their equivalent to DNA, flesh and the soul/heart (CNA, living metal and the spark respectively) as well as being not just alive in mind, but also body.

    Tabletop Games 
  • Dungeons & Dragons
    • Crystal spiders from Dark Sun.
    • Planescape has many creatures native or related to Elemental Plane of Earth and Quasielemental Plane of Mineral both consisting of (and feeding on) some or other mineral matter.
    • The Shardmind from 4th Edition are an entire race of humanoid new age psychic crystals.
    • 1st Edition Monster Manual II
      • The Sandling is a silicon-based creature from the Elemental Plane of Earth.
      • The Storoper has a silicon-based rock-like body.
    • 1st Edition Fiend Folio. The Flail Snail is described as a "silicon-based mollusc".
  • Traveller
    • Classic Journal of the Travellers' Aid Society #15 article "The Bestiary". Doyle's eel is a silicon-based life form that eats metal. If it infiltrates a starship it will try to eat metals, silicon and some plastics, which can cause serious damage. It will also try to lay eggs and hatch out more of them, which will cause even more damage.
    • Marc Miller's Traveller supplement Milieu 0 Campaign, chapter "The First Wave". In one of the Survey adventures, the PCs can encounter large rock-like creatures that are silicon life-forms. They are serpent-like and can project lava jets as a weapon.
    • FASA adventure Ordeal By Eshaar. The native life forms on the planet Eshaar are silicon based and appear to be crystal/rock formations. They combine water and liquid sulfer to create sulfuric acid, then combine the acid with various metals to create energy, acting like living batteries.
    • In Adventure 13 Signal GK, the PCs will encounter a naturally occurring silicon computer chip that has become intelligent.
    • The Artificial Intelligence Virus in the Traveller: The New Era setting, which was engineered from sentient computer chips from Cymbeline previously featured in Adventure 13: Signal GK.
    • Spacefarer's Guide to Alien Monsters
      • The mante is an alien insect whose tissues are composed of silicon. This makes its body extremely dense, and it is not affected by most weapons.
      • The rockrat's body tissues are based on silicon, which makes them immune to all physical attacks except energy weapons.
      • The sizzler is a two meter wide ball of black stone based on silicon which eats its way through rock.
    • Magazine The Traveller Chronicle, issue #4 article "Astrogator's Update to Diaspora Sector". The planet Netti has the "chip chicken", a silicon-based alien creature that eats basalt and breathes methane. Its waste products are silicate crystal nodules that can be used as computer data chips.
  • Towsers in Myriad Song may look like oddly colored dogs, but their bodies are composed of silicon and rare earths. They eat polysiloxanes, are immune to metal-based poisons, and can get oxygen from carbon monoxide (carbon dioxide is still deadly though).
  • Star Frontiers adventure SF1 Volturnus, Planet of Mystery. The Eorna created silicon-based life in the form of large crystals. Their attempts to make the crystals intelligent failed, as whenever they reached semi-intelligence, they Turned Against Their Masters.
  • Chaosium supplement All the Worlds' Monsters
    • Volume I
      • The rock dragon's body is based on silicon.
      • The furred flyer and furred one are silicon-based life forms that eat silicon mineral deposits for food.
    • Volume III. The Zend-Avesta is a telepathic silicon based life form that gets its energy from sunlight and looks like a spherical white globe hovering in the air.
  • Lords of Creation RPG, Heroes magazine Volume 1 #1 article "Survival Run of the Starnomads". The flamewolf is an alien creature (resembling a large wolf) made out of rock. They are silicon-based life forms, with saliva and blood that burst into flames in the presence of oxygen.
  • Ares magazine #6 game "Voyage of the BSM Pandora". One of the possible encounters in the game is a huge silicon-based monster which is powerful enough to pulverize one of the expedition's robots.
  • GURPS Space Bestiary
    • The Fridge is a silicon-based life form that lives in arctic regions and looks like a grey rock up to three feet high. It kills other creatures by lowering the temperature nearby, doing 1-6 Hit Points of damage per second.
    • The Volcano Beast is an arctic silicon-based predator that hunts by generating a burst of intense heat that roasts nearby animals. It takes the form of a dark grey cone 4 yards tall.
    • The Warmer is an arctic silicon-based life form that looks like an amorphous grey rock a yard wide. It generates heat to melt through snow so it can eat the vegetation underneath.
    • The Mine is a silicon-based creature that looks like a three yard wide pink rock and weighs one ton. It lives underground and kills its prey by detonating an explosive gas.
    • The Skylens are predators that are transparent, silicon disks about three feet in diameter, attacking their targets with sun rays. They locomote by psychokinesis.
  • Shadowrun: Rockworms are about as close as Earth life can get to this even under the influence of magic. They still retain carbon-based DNA — silicon atoms are far too large to fit within its structure — but utilize silicon in most other systems, require carbon only in trace amounts and get along by eating silicate minerals as their chief food source.
  • Battlelords of the 23rd Century
    • Supplement Galactic Underground II. The Gemini are a race of silicon based life forms that resemble humanoids made out of living rock. They love precious gems and other crystals.
    • Supplement No Man's Land: Planetary Atlas. The mining planet Jaloon has silicon-based arthropods who are shaped like manta rays. Both the natural animals and giant mutated versions have attacked and eaten miners.
  • Alternity RPG, Star*Drive campaign setting, Dungeon magazine #68 adventure "Convergence". The alien race known as the Rakon are "silicates": their biology is based on silicon instead of carbon.

    Video Games 
  • Gunman Chronicles uses it as a plot point, where Silicon lifeforms can't digest Carbon lifeforms.
  • Ruina: Fairy Tale of the Forgotten Ruins: After the Nightseed attack on the town, several children, including Chuna, slowly have their bodies enveloped by sentient purple crystals. These are later revealed to be Star Spirits, which force their victims to dream.
  • Star Control:
    • The Chenjesu are essentially sapient crystals. They are living hyperspace receivers more sensitive than most sentients who tried managed to build and make pretty much anything from crystalline materials.
    • The Taalo in the games' backstory as well, though they were living rocks rather than specifically crystals. Their unique physiology is what enabled them to make friends with the Ur-Quan (who, being predators, usually feel an overwhelming instinct to eat other creatures they come into contact with... but rocks don't provoke that instinct).
  • Master of Orion: The Silicoids. The wildly divergent biochemistry of silicon-based organisms is reflected in the gameplay. Silicoids do not need to farm to produce food, thus freeing up their population to conduct research or construction. In addition, they are immune to the effects of pollution and can live on even the harshest planets without a problem. On the down side, their slower metabolism means slower population growth, and their vastly different psychology makes it nearly impossible to deal with other races diplomatically.
    • Also, the Space Crystal monster, which flies around and exterminates the population of colonized planets.
  • Metroid Prime: Hunters has this in Spire, whose race (the diamonts) are silicon-based lifeforms.
  • The Gastro, from The Maw, are silicon-based organisms.
  • Sword of the Stars has the Swarm, bee-like things that spawn from asteroid hives and fire plasma, as well as sending out Silicoid Queens to build new hives. They are Demonic Spiders, especially in early game or with small groups, but reward you with a fair amount of resources if you clear a hive.
  • Technically, most Rock-type Pokémon count, as several of them are literally made of rocks. Same goes for many Ground-type and Steel-Type Pokémon. Porygon is either this trope or an android. (It's hard to tell.)
  • The Silacoids from X-COM: UFO Defense are simple silicon-based life forms that look like lumps of purple lava. They have rock-hard skin that is immune to fire damage and attack by biting. Because of their extremely high body temperature, they leave burn marks on the ground as they move, sometimes setting fire to nearby objects.
    • In XCOM: Enemy Unknown, researchers are forced to admit that they have no idea whether the Cyberdisks are living or purely mechanical, but conclude that if they are living, then they're probably silicon-based lifeforms. The Sectopods, on the other hand, are alive, and are silicon-based.
  • Terraria:
    • The Meteor Heads. They are flying Mooks that spawn at meteorites and attack en masse.
    • Version 1.3 introduced Granite Cave sub-biomes, which feature Granite Elementals and Granite Golems.
  • Crystals in VGA Planets, who are an Expy of Star Trek's Tholians, including perfering to live on hot planets.
  • Muv-Luv: The BETA's creators are this, and have programmed the BETA to recognize only silicon life as lifeforms. The BETA are therefore incapable of seeing carbon-based life, such as humans, as living things, and don't even think they're fighting a war. From their point of view they're recycling resources. Ironically, the BETA themselves are carbon-based.
  • In Duke Nukem Forever, on the alien ship there are breasts growing out of the wall. Duke will make a quip if you slap them, one of which is "Hmm, some strange silicon(e) based life form."
  • The Kessok from Star Trek: Bridge Commander.
  • In Sacrifice, the wizard Grakkus is made from living rock.
  • WildStar has the Granok, made of "living rock," and the Osun, made of metal. Both are Proud Warrior Race Guys.
  • An enemy in Borderlands 2 are "crystalisks", which are tripodal organisms made of living rock and crystal — the base of each leg features a large patch of golden crystal, their only vulnerable spot, and they drop over a dozen valuable crystal shards upon death. One quest, leading into a long-abandoned mine called the Caustic Caverns, revolves around recovering an Apocalyptic Log that reveals that the crystalisks are actually highly intelligent and were friendly when humans first arrived. The security forces for the first mining expedition even made friends with them. When the profit-orientated mining officer demanded that the crystalisks be harvested, the security officers tried to revolt, but crumpled after their leader was killed. The crystalisks angrily rose up in self-defense and slaughtered the mining team, resulting in the closing of the mine, and they've been hostile towards humans ever since.
  • Xenoblade Chronicles X: The Milsaadi are said to be silicon-based. They have metallic skin and their voices have a strange reverb to them, but they are definitely stated to not be mechanical. Given the Milsaadi's lack of relevance though, this ends up just being a trivia bit, not related to the plot at all.
  • Inara and Terminus from Paladins are members of a race of stone-skinned people called Stagala. Inara is a normal Stagala with the power to manipulate the earth, while Terminus is an undead warrior who fights using his massive axe and undead magic.
  • The Legend of Zelda: Gorons seem to be this. It's never outright stated, but they eat rocks and can take a lava bath without harm.
  • Mass Effect: Though you don't encounter them in game, the Flavor Text for the planet Sharjila mentions it has a silicon-based animal ecology. With the series thorough aversion of All Planets Are Earthlike, these animals live on a Death World of 40 atmospheres worth of pressure; even if you didn't get crushed by the atmosphere, large swaths of the planet are covered in silica dust—the byproducts of the ecology's respiratory processes—which is very easily disturbed by anything more powerful than a brisk gust. You thought sandstorms on Earth were bad? Try breathing in a hurricane of microscopic glass shards. Suffice to say, wearing an exosuit is mandatory while exploring the surface.
  • Stellaris: Although it's never explicitly stated what exactly the Crystalline Entities are, the fact that they're, well, spiky crystals roaming through space lends itself to the hypothesis that they're silicon-based. They're described as ultra-hard bordering on unbreakable, and researching their remains unlocks special ship modules that give a nice bonus to hullpoints. There's also a random event unrelated to the Crystalline Entities that's outright named "Silicon-Based Lifeforms", but this one merely adds a +3 minerals deposit to the celestial body it's found on.
    • The Lithoids DLC adds silicon-based playable species that eat minerals instead of food and have a set of unique traits that cause them to excrete strategic resources. They can also have a "Calamitous Birth" origin where their species was born from a strange meteorite, which they can recreate as colony ships that make impacted planets less inhabitable to other species, and Hive Minded lithoids can become literal Planet Eaters.
  • The now-defunct 2009 MMO Nanovor revolved around the titular mons which were a race of microscopic insectoids living within silicon microchips.
  • One version of Ahnonay accessible in the "Path of the Shell" expansion to Uru: Ages Beyond Myst is made up of barren rocks dotted by white, spiky crystalline trees. Presumably they're an example of this, although you never get a chance to confirm it.

    Web Comics 
  • Schlock Mercenary: A halfway house between this and regular life: Sergeant Schlock, who is carbosilicate (i.e. based around both carbon and silicon). In a bit of realism, his biology and biochemistry is pretty clearly shown to be fundamentally different from traditional carbon-based life.
  • Vexxarr has two silicon-based species, both living in space. "Rock crabs" such as "Sid" (Silicon dioxide, get it?) are practically indestructible and feed off of radiation, while silicoid predators eat rock crabs and explode if fed cake. Both species are typically found roughly human-sized but grow to the size of asteroids.

    Web Original 
  • SCP Foundation
    • SCP-227 ("Silicon-Based Lifeform"). This deleted entry described a vaguely humanoid 10 meter high creature with a polyp-like head. Its siliconate skin makes it Immune to Bullets.
    • SCP-229 ("Wire Weed"). Foundation scientists tentatively identified SCP-229 (a mass of wires and electrical cables) as a form of silicon-based life.
    • SCP-440 ("Sand-Based Ecology"). Several types of creatures are made up of SCP-440, which is an anomalous form of sand. The sand is made up of silica (silicon dioxide).
    • SCP-507 ("The Reluctant Dimension Hopper"). On one of SCP-507's trips he ended up in a dimension with living, moving crystals based on silicon. They're described as looking like crustaceans and may be connected to SCP-440, which also creates crustacean-like silicon-based life.
    • SCP-553 ("Crystalline Butterflies"). The title creatures have a silicon-based biochemistry and are composed primarily of calcium and silicate compounds.
    • SCP-1073 ("Computing Microbes"). SCP-1073 are sapient silicon-based microbes that can receive and understand radio waves.
    • SCP-1107 ("A Signal"). A group of asteroid-like bodies in the Kuiper Belt and the Oort Cloud around the solar system contain unusually pure silicon and silicate based crystals. They absorb solar radiation and use the energy to generate radio signals. Analysis of the signals indicates that they're not only alive, but intelligent.
    • SCP-2300 ("Periodic Golems"). Ninety-eight Lilliputians made from the elements hydrogen to californium; SCP-2300-14 is the one made from pure silicon.
    • SCP-2622 ("Ambassador from the Mole People"). According to SCP-2622's stories there's a cavern called “The Fire Plain” located under the south-central Pacific Ocean. It's inhabited by silicon-based crystal animals.
    • SCP-2978 ("Motherburg"). SCP-2978-B are a race of tiny silicon-based humanoids. They live in the silicon chips of computer motherboards and are experts at using and modifying computers.
    • SCP-3284-J ("Lava Sharks"). These are shark-like creatures that live in lava pools and can swim through them the way normal sharks swim through water. They don't need to eat but attack and consume living creatures anyway.
  • DSBT InsaniT: Sand Snake is made of, well, sand. Likewise, Crystal Dragon is made of, well, crystal.
    • Eel, the Big Bad, is an eel made of stone.

    Western Animation 
  • Invasion America has a genetically engineered species called manglers. A baffled human scientist describes the discovered bones of one as a "silicon analog" rather than carbon-based.
  • This trope is invoked in the episode of The Simpsons when Homer encounters an alien.
    Homer: I'd be happy to answer your questions about the alien. Any questions at all.
    Dr. Hibert: Is the alien carbon-based or silicon-based?
    Homer: Uh... the second one. Silliphone.
  • Diamondhead and his expy, Chromastone, as well as Echo Echo, in Ben 10. The difference with Echo Echo is it's species is not totally silicon: its body is a suit made of silicon to hold its real body, which is a sonic wave.
  • In one episode of Flash Gordon (1979), Ming the Merciless creates a silicon-based monster and unleashedsit on the heroes. The heroes' weapons have no effect on the creature because, in their words, they're shooting sand.
  • Futurama: The aptly named Silicon Red, a folk singer resembling a bearded humanoid made out of stone and one of Bender's celebrity idols (asides Elzar and Calculon) from "Forty Percent Leadbelly".
  • Infinity Train has a whole train car full of these beings in the episode "The Crystal Car". These include crystal hippos, crystal birds, and a helpful crystal gentleman named Greige.
  • The inhabitants of Planet Rock in Shadow Raiders are this crossed with Green-Skinned Space Babe—stone creatures that look almost exactly like blue or green-skinned humans.

    Real Life 
  • Silicon is more abundant than carbon on the Earth's surface, and yet Earth life is almost exclusively carbon-based. Compared to carbon, silicon only presents an advantage in temperatures around 150°C, where silicon bonds would remain stable while their carbon counterparts break down. It is speculated that such silicon-based life would use siloxane backbones (alternating silicon-oxygen chain), as siloxanes can form a wide variety of polymers, and would probably use sulfuric acid as a solvent and respire fluorine gas. Such life would be prone to exploding on contact with an earth-like atmosphere.
    • Hypothetical sulfur and fluorosiloxane based-life would live in even hotter environments and, at the hotter end, use molten rock as a solvent.
  • While life on Earth is carbon-based in its molecular structure, one origin-of-life theory posits that organic molecules could've initially begun copying themselves on the surfaces of wet clays. As clays do contain silicon, this would make "silicon-based life" true in a literal sense.
  • While it isn't used in place of carbon, plenty of Earth organisms do use silicon for various purposes. Sponges use silicon in their skeletal structure, grass uses it as an abrasive to render itself less palatable as a food source, and diatoms use silica to produce their frustules (hard outer coatings).

Alternative Title(s): Exotic Element Based Life, Non Carbon Based Life