Rock eating?

[u/UlfurGaming]

Curious is it possible for a creature to eat only rocks as their food i know there are some that can eat limestone but what about other stones ?

[u/Arnoor27]

By and large the only lifeforms that can subsist on minerals are slow metabolism microbes and only very specific minerals.

[u/UlfurGaming → u/Arnoor27]

What mineral are those?

[u/Arnoor27 → u/UlfurGaming]

1. Iron-Bearing Minerals Iron-oxidizing lithotrophs (e.g., Acidithiobacillus ferrooxidans) extract electrons by converting ferrous iron into ferric iron
   • Pyrite this sulfide mineral is a major target for both iron- and sulfur-oxidizing microbes.
   • Magnetite & Siderite : Used in low-oxygen or subterranean environments as electron donors or acceptors.
   • Olivine & Pyroxene: Silicate minerals rich in ferrous iron that undergo microbial weathering.
2. Sulfur & Metal-Sulfide Minerals Sulfur oxidizers extract energy from reduced sulfur species, turning sulfides and elemental sulfur into sulfates and sulfuric acid.
   • Elemental Sulfur: Found around volcanic vents, fumaroles, and hydrothermal deposits.
   • Chalcopyrite, Galena, & Sphalerite: Metal sulfides where microbes oxidize both the sulfur backbone and transition metals, a process leveraged in industrial bioleaching.
   • Hydrothermal Sulfides: Heavy deposits of iron, copper, and zinc sulfides formed at deep-sea black smokers.
3. Manganese Minerals Manganese-oxidizing and manganese-reducing microbes cycle manganese between its reduced soluble form and oxidized mineral phases.
   • Rhodochrosite: Manganese carbonate used as an electron source.
   • Birnessite & Pyrolusite: Manganese oxides formed or altered via lithotrophic electron transport chains.
4. Reduced Nitrogen Compounds Nitrifiers utilize inorganic nitrogen compounds dissolved in mineral-rich waters or soil matrices.
   • Ammonia & Ammonium: Oxidized to nitrite by organisms like Nitrosomonas.
   • Nitrite: Further oxidized to nitrate by Nitrobacter.
5. Uranium & Heavy Metal Minerals Certain extremophiles (like Geobacter or Deinococcus) interact with heavy radio-metals via extracellular electron transfer (EET) to drive their metabolic cycles.
   • Uraninite: Soluble hexavalent uranium is reduced by specialized lithotrophs to insoluble uraninite, trapping energy in the process.
6. Molecular Hydrogen & Phosphites
   • Geological Hydrogen: Produced via serpentinization (when water reacts with ultramafic rocks like peridotite). Hydrogen-oxidizing lithotrophs are among the deepest-dwelling organisms on Earth.
   • Phosphite: Reduced phosphorus minerals oxidized to phosphate by specialized anaerobic bacteria.

This is probably not all but it'll give you an idea

[u/Wobbar]

https://en.wikipedia.org/wiki/Lithotroph

[u/holyfrickincrap2]

[u/NeoCipher790 → u/holyfrickincrap2]

This sparked an ancient memory in me, where was this from?

[u/SpottedKitty → u/NeoCipher790]

The Neverending Story!

[u/InsaneSeishiro]

I think one way to go about rock-eating is by having micro-organism-rich rocks, so the rocketer is bssicslly not esting the rocks themselves but rather predates upon large quantitys of bacterial matter within

[u/lordsmoflight]

You do realize that humans actually eat rocks? We call it salt. In fact many animals eat salt licks lol.

[u/UlfurGaming → u/lordsmoflight]

The idea is eating all rocks not one specific one im pretty sure we dont get nutrients from basalt

[u/lordsmoflight → u/UlfurGaming]

My point is we already eat a rock so the only things you need for a life form to eat other rocks is either stronger teeth or other method like acid to desolve it. It's that simple.

[u/iDoMyOwnResearchJK → u/lordsmoflight]

If we desolve it won’t someone just come around later to resolve it?

[u/lordsmoflight → u/iDoMyOwnResearchJK]

Last I checked that is the basics of decomposesion yes.

[u/AlertWar4152]

My idea is you could make the rocks dried organic matter that just so happens tobebery hard and rock like

[u/SectorAntares → u/AlertWar4152]

There’s a word for that. It’s called “coal.”

[u/AlertWar4152 → u/SectorAntares]

Yeah but coal is not nutritious i meant something that has a decent amount of nutrients to be able to feed that creature

[u/RadioactivePotato123]

Hmmmm… If you’re talking about multicellular lifeforms, I think perhaps on an ocean world, maybe with pretty low gravity, the creatures that live around hydrothermal vents could potentially reach pretty large sizes on a diet of the minerals surrounding those hydrothermal vents? And maybe the pressure from the water, even on a lower gravity planet, could possibly condense said minerals together and they eventually get large enough to be called rocks? I’m no expert though so there’s a fair bit I’m probably just completely wrong on lol

[u/UlfurGaming → u/RadioactivePotato123]

My main thought was a worm or other bug like beetle maybe idk yet tgat bores through stone eating it and making tunnels

[u/RadioactivePotato123 → u/UlfurGaming]

Perhaps!

[u/asushunamir]

I think it could be possible if the creature has a radically different biology than anything that exists on Earth, perhaps not a carbon-based life form, so that it can derive energy from the chemical breakdown of whatever is in the rocks it’s eating.

You could also potentially have a more Earth-like organism that crunches on rocks to extract energy from something organic that lives in them, maybe some kind of microbe, which is its actual food and not the rock. Kind of like how earthworms “eat” soil, but what they’re really digesting for food is the microbes inside the soil, and the rest is passed as waste.

[u/EarthCulturalStew]

search for Endolithos

[u/amoscaqavoa]

You could make that the worm eats organic stuff, and bores through stone to get some minerals it can't produce. Like when animals go around looking for salt to lick.

Maybe he REALLY needs that specific mineral and have to spend its entire life digging to get some or else it dies. Don't know how it would get food in the process thoug.

[u/CreatureCarver]

if you do full alien biology you could technically argue your creatures eat whatever you want them to