Metals, especially iron and copper, are a critical part of a typical human civilization. A common setting in science fiction and fantasy is a world that is lacking in these materials. This lack can be used to drive the plot, or simply to provide an unusual background for the story.
This can be a reason for a Medieval Stasis or the driving force behind the development of Magitek or Organic Technology. Bamboo Technology is a possible (but uncommon) outcome. A dangerous Metal Muncher might be banished to such a planet where it can do no harm.
There is an element of Zeerust to this trope, as real world advances in materials science is increasingly demonstrating the ways in which elements like carbon and silicon can be used to produce both structural materials and electronic components with little or no iron, copper or other traditionally used metals. In particular, many works in the science fiction genre start with the assumption that virtually all future technology would be based on metals like iron, and that the lack of it would result in a technological collapse since nobody could conceive of using anything else. That said, so far as we can tell, developing the technologies needed to refine carbon and silicon into substitutes for metal would require metalworking to be developed first. A neolithic or medieval society on a planet with little or no metal would not realistically be able to advance to a modern level of technology, and as such would not be able to develop the ability to manufacture non-metallic technologies.
- Marvel's Crystar, Crystal Warrior has a variation. It's set on the planet Crystallium, which, as its name suggests, is so full of huge impressive crystals that they're literally as common as rocks, and crystal is their primary building material. They may be poor in metal, though it's never lampshaded (armor tends to be made of dragonhide, as reptiles of varying types, both big and tiny but generically called "dragons," seem to dominate the ecosystem), but the crystal is so abundant that it serves their needs just as well. What they're really lacking, we learn when they visit Doctor Strange on Earth, is wood. They're astonished at the incalculable wealth represented by his wooden furniture and big bookcases full of paper books.
- Isaac Asimov's Foundation Series: Terminus, in addition to being the farthest planet from the galactic core, has so few mineral resources that it was considered nearly worthless. It therefore became a useful place to exile Hari Seldon and those sympathetic to his cause. Fifty years after the Foundation was established, they are so starved for resources that their coins are made from steel. Salvor Hardin uses their lack of materials as an excuse to ask the envoy from Anacreon if they had any plutonium available for trade, since the reactors on Terminus could use more. It's a ruse to see how far their technology has regressed as Terminus doesn't use metals like plutonium in their nuclear reactors. Without the abundant resources of Trantor, they've had to push miniaturization to levels that scientists of the first Galactic Empire had believed impossible.
"The planet, Terminus, by itself cannot support a mechanized civilization. It lacks metals. You know that. It hasn't a trace of iron, copper, or aluminum in the surface rocks, and precious little of anything else." — Salvor Hardin
- In Marion Zimmer Bradley's Darkover series, the planet Darkover (Cottman IV) has a lack of metals compared to most Earth-type planets. The novel Darkover Landfall said that the planet didn't have a nickel/iron core, that the rock was low in metallic ores and that metals were very rare. The locals have developed Psychic Powers to a level verging on Magitek.
- Many of the worlds in the Childe Cycle lack metal resources, and as a result have to import it. And because these worlds lack these resources (among others) it affects their economy in interstellar trade.
- The Cinder Spires: Metal is plentiful enough (the really rare material is wood), but, due to a quirk in the composition of the atmosphere, any metallic iron exposed to the air will rust away into nothing in a matter of days.
- The CoDominium series:
- In King David's Spaceship, Prince Samual's World is noted to be copper poor. As a result, one Imperial thinks that world will have trouble building communication lines without imports of the metal.
- The Mote in God's Eye has Mote Prime. Because they've been trapped in their star system, the Moties have mined out their metals and have to scavenge from older relics.
- Dragonriders of Pern. The planet Pern has limited amounts of available metal, meaning it is of little interest to the large corporations that normally colonize worlds, but perfect for a group of people who want to create a low-tech agrarian society. At one point it's revealed that the planet's name was originally an acronym for Parallels Earth, Resources Negligible.
- Leo Frankowski's New Kashubia Series: An Invertion, as New Kashubia is made up of concentric rings of metal and really quite sucky to live on at first.
- Great Ship: In Eater-Of-Bone, a colony ship was catastrophically damaged and flung off of its trajectory, sending it towards one of the lone stars at the periphery of the Milky Way. The nigh-immortal Trans Human colonists are forced to settle on a world which is extremely metal-poor (particularly in salts and iron), making any kind of machinery precious beyond belief and every drop of blood lost a tragedy. One character laments that there's metal in the world, but so far below the ground that it is unreachable to the damaged machinery of the starship. The colonists cooperated with each other for a short time, but the strains of resource shortages fractured them into dozens of small groups, who often fight each other for resources. "Eater-of-bone" isn't meaningless, either, because even bone and marrow hold the metals required for metabolism.
- Harry Harrison's "The Pliable Animal": Andriad has few metals, so table knives and coins are made from tempered glass.
- Honor Harrington has this issue inverted on the planet Grayson, which has far more heavy metals than Earth. The colonists that had gone to Grayson had intended to forgo all high technology (believing the planet to be their Promised Land and technology to be a temptation by Satan) and still tried to do that, making a bad situation much worse while some practical religious leadership worked hard to square their ideals with reality. Some of the last remaining technology was used to genetically engineer higher resistance to heavy metals, but at the cost of a 1/3 male/female birth ratio, accentuating the conservative patriarchy of an already polygamous society (they are roughly Space Mormons with Japanese influences). By the time of the series a millennium later, the planet is still behind the galactic technology curve, but has domed cities, orbital farms, and better fission technology than anyone else since they forgot fusion and had loads of uranium lying about.
- Last and First Men: The Early First Men (meaning modern-day humanity up until the collapse of the world state four thousand years hence) exhausted all metal deposits in the shallow crust (alongside all coal and oil deposits, for that matter). Thus, after the collapse of global civilization, Earth has no readily accessible sources of workable metal and humanity remains stuck in a stone-age agricultural state for millennia. This is eventually resolved when the devastating eruptions that destroyed the last First Man civilization scatter layers of metal-rich debris throughout the Earth's surface.
- The titular planet in the Majipoor Series is ten times the size of Earth, and only habitable thanks to this trope. The lack of metal leads to Schizo Tech, with draft animals and Vibroweapons existing side by side.
- Larry Niven
- The Integral Trees: There is effectively no metal whatsoever in the Gas Torus where a Lost Colony of humanity is located; as such, all materials are made from local wood from the kilometer-long trees in the gas torus spinning around the neutron star. What little metal there is has been recycled endlessly from what the colonists brought with them.
- Ringworld, an unimaginably large artificial world, has no mineral ores: if you dig into a mountain, you'll hit the scrith underlying the sculpted landscape after a few hundred meters. After the civilization that built the Ring collapses, a space-faring civilization can't rise again because there's no ore and you can only recover so much metal from ruined cities.
- Revelation Space Series: The first civilizations in the galaxy developed on these owing to the effect described in the Real Life section, leading to a series of galaxy-spanning wars over valuable supplies of metal. This led directly to the creation of the Inhibitors, whose belief that intelligent life is inherently warlike means that all intelligent life must be suppressed once it develops interstellar travel, or they'll cause all sorts of mayhem again.
- H. Beam Piper's Space Viking: The planet Amaterasu lacks fissionable metals, causing them to regress to the industrial age after the Old Federation collapses. However, they have large deposits of an Unobtainium used in FTL drives that require nuclear power. When the protagonist realizes that another planet he raided had fissionables but no unobtainium he decides it would be more worthwhile to trade between the two planets instead of raiding them.
- A Planet Called Treason: In the backstory, a group of families attempted to overthrow the government of an interstellar republic and as punishment were banished to a planet without any accessible iron. Each family is given a teleportation device with the understanding that if they place something of sufficient value in it, they will be rewarded with iron. The story starts off when one of the families, now grown into a nation, starts conquering their neighbors using improbable numbers of iron weapons.
- The Riftwar Cycle starts when magicians from metal-poor Kelewan develop a way to create rifts leading to other worlds. Scouts report that the world of Midkemia has unimaginable wealth in metal just lying around; a Midkemian viewing a magical recording of the events recognizes the "wealth" as being trash heaps and slag piles.
- Riverworld: The titular world was intentionally built without access to metals as a way to get every human who ever lived and has been resurrected at the same time to concentrate on more spiritual issues.
- In the Seekers of the Sky, Earth itself was miraculously stripped of most of its minable iron in the backstory, leading to a civilization that is still struggling with industrialization around 2000 and where bronze swords are still common weapons.
- Spinneret involves humans colonizing an Earthlike planet with absolutely no surface metal, not even metal salts in the oceans, because it's the only world available. As a result, anything metallic — even fertilizer for crops — needs to be brought in from Earth. They very quickly discover why: there's an alien device that leeches metal out of the soil (or even merely in contact with the soil) and turns it into kilometers-long strands of super-strong cable.
- E. E. "Doc" Smith was fond of this:
- In Triplanetary, the planet Nevia is so scarce in iron that ten pounds of it is an unimaginably large quantity; this scarcity, combined with the Nevians' development of a method for total mass-energy conversion of iron, gives iron a value so starkly indescribable that the Nevians invade our solar system in search of it.
- In The Skylark of Space, Osnome is rich in heavier elements but poor in sodium and/or chlorine, so that common salt — an essential part of the Osnomians' process for making the super-tough material arenak — is extremely rare and valuable; the quantity of salt in Seaton's cruet is said to be greater than the total amount known to exist on Osnome. There is also an inversion in that "X", the nameless quasi-stable transuranic element that catalyses the mass-energy conversion of copper, while vanishingly rare on Earth, is found to be so common on some distant planet that entire cliffs and mountains are made of native X. Apart from the scarcity of X, none of these vagaries of elemental abundance are remotely plausible by the light of today's knowledge, but at the time Smith was writing the processes of stellar nucleosynthesis for elements beyond helium were unknown, and more or less any distribution was as plausible as any other.
- Takis in the Wild Cards series. However, this merely served to push the Takisians towards Organic Technology, which they have mastered to the point of literally being able to grow things like space stations and travel through space in Living Ships.
- The first Red Dwarf novel says that Earth has been completely mined dry by the 22nd century, necessitating humanity to colonize and mine the rest of the solar system. Hence massive mining space ships like the titular vessel.
- The Orson Scott Card novel Wyrms takes place on a human colony world whose largest and most accessible deposits of iron and coal were destroyed from orbit by the colony shipís captain, under the psychic thrall of something on the planet below. Iron being scarce made steel incredibly rare and valuable, forcing the colonists into Medieval Stasis.
- Dungeons & Dragons' Dark Sun: This setting is very poor in metals, which is why obsidian is commonly used for swords, armor, and such.
- Eclipse Phase: Solemn is infested with a bacterium that eats exposed metal, making it a bit of a Death World to Synthetic characters or those with external cyberware.
- Empire of the Petal Throne: Set on a planet with few metals and tropical climate, these effects limit the armour available to characters.
- A lore book included in the Beyond Light expansion for Destiny 2 describes the "Forge Star", a megastructure built by the Vex billions of years ago to extract metal from the star 2082 Volantis, because it was otherwise difficult to find on planets during that era of the galaxy.
- Seedship: You can find a metal poor planet while looking for a new home for humanity. If you settle on such a planet, the human colony will eventually suffer technological recession to either medieval, industrial or atomic (only if you managed to enrich scientific database of your seedship before or settled on a planet with high-tech ruins) level of technology. The colony may avoid that recession if planet has a metal-rich moon, in which case, they'll build a rocket and mine metals from the moon.
- Planets in the Master of Orion series have randomly generated traits, including size, biome type, and mineral content. Planets that are poor in minerals suffer a significant penalty to industrial production, but may be useful for agricultural production.
- Some planets in Stellaris that are otherwise habitable may be discovered to be metal-poor after surveying. Since you're already an interstellar nation it isn't a debilitating situation since minerals can be imported, but it does reduce the maximum number of mining districts allowed on the planet and those that are built are less productive than usual.
- Ardenweald, one of the afterlives in World of Warcraft is an entire realm devoid of metal or any kind of stone at all. Being the afterlife most closely tied to nature, everything apart from the dirt is alive. Any tools or equipment the Night Fae use, from carts to roads to weapons, are made of wood, plant matter, or amber.
- Valheim: Zigzagged in that while metal ore is (relatively) abundant, processing it into usable metal is a time-consuming project . Dragging the ore back to the camp or smelting it on site (as metal and ore can't be teleported) are equally dangerous due to the ever-present possibility of being attacked. They can only be mined once you have a pickaxe (made from materials dropped by the first Forsaken), with more advanced materials requiring the items dropped by the other bosses.
- Copper and tin are found as deposits in the Black Forest, meaning mining operations are routinely interrupted by greydwarves and trolls.
- Iron is present in the Swamp biome, but it's buried at random, meaning you need to defeat its boss to get The Little Detecto item. A much better source are the sunken crypts, which are both infested with draugr and depend on the seed (some worlds have swamps where you're always in sight of a crypt, others don't have a single one for miles around.
- Silver mines are buried underground in the mountains and spawn at random, meaning you can freeze to death looking for one if the wolves and drakes don't get you first.
- Black metal is actually quite easy to find as it's always dropped by fulings, you just need to survive killing hundreds of the little bastards to get it in useful quantities.
- Mara: While metal exists, it is rare enough that seeing someone with a metal weapon is noteworthy. Most weapons have bone or stone blades.
- Sins Venials: Word of God says this is why the world never seemed to advance beyond the medieval level: metal was just too scarce.
- Tales of the Questor: has the Land of Antilla, a land of Racoon people with no viable metal mines, thus they are forced to continually industrially recycle what metal they have until that means is exhausted. However, a brilliant botanist in a seemingly hopeless, and technically illegal, agricultural project, has stumbled onto a way to organically extract bauxite from the soil and bring forth berries of pure aluminum, a metal that was almost impossible to refine in that world's technological level.
- Freeman's Mind: Gordon Freeman theorizes that the lightning spewing aliens come from a mineral poor planet. He offers to share Earth's prodigious mineral wealth... at high velocities.
Gordon: All I need are bullets. We have a lot of bullets here! EARTH! IS A MINERAL! RICH! PLANET! I BET YOURS SUCKS! Itís probably a swamp planet, with no metal! And if itís not you belong in a swamp anyway!
- In Amphibia, Amphibia is implied to be fairly resource poor, as their society has remained in Medieval Stasis for a millenium. While they had technology exceeding that of present-day Earth in the past, this was gained by exploiting other worlds using the Calamity Box, and their advanced civilization collapsed when it was stolen.
- Within the first thirty minutes after the Big Bang, primordial nucleosynthesis produced large quantities of hydrogen and helium, a smattering of lithium, and nothing else. The hypothetical Population III stars were the first generation of stars formed from that original matter, and consequentially they had almost no metals* outside of those being formed in their core through fusion. The next generation (Population II) contained more heavy elements that had been released from the Population III stars' cores by supernovae, while the Population I stars (which include our Sun) have even higher proportions of metallic elements. Consequentially, planets from Population II and III stars are expected to be very metal-poor.