The simplest "why" would be just to say that their was either no source of high heat (needed for forging and refining) or just no source of metals in the world (no or very few metal-bearing rocks).

That's what I'm leaning towards. My concern is then how cities would look, how war would be waged, and so on, since metal has played such a crucial part in the development of our own world.

Did anyone else think "Flintstones"? :P

A good example of a metal-poor world in existing fiction is that of Kelewan from Raymond E. Feist's Riftwar Saga. The branch of humans living on that world (the Tsurani) use lacquer covered cured hides and wooden weapons which have roughly the same strength of their metal counterparts. If I recall correctly, there was both a specific type of tree with strong but supple wood, and a hardening process for that wood that could make it mimic the strength and sharpness of metal.

That was essentially the sort of adaptations I've been toying with for my own world, primarily a mixture of woodwork and alchemy. I'll look into Kelewan and see if there's anything to be gleaned there. Thanks.

@MariaLin One thing to note is that magic is present in that universe, which allows them to do many things that may be otherwise difficult or impossible without the assistance of metals.

My world is heavily focused on magic, but I wanted to know where the holes were that magic would need to fill in, so to speak. I'm thinking now that my question was badly worded, but live and learn.

Are ceramics viable? You can do quite a bit with modern ceramics that a culture without metal may discover sooner.

Michael Z. Williamson's Contact with Chaos is an enjoyable pure SF story involving first contact with aliens on an extremely metal poor planet. It's been several years since I read it; but IIRC while their visible tech base wasn't much beyond what human neolithic civilizations had achieved they had a lot of ceramic and catalytic chemistry technology that they were initially concealing from the humans. While it is the 3rd book in the series, it works well as a stand alone (details of why the two human factions loathe each other aren't essential) and has a very different feel than he others.

Horn and ivory may also be metal substitutes sometimes.

It's a complete side note, but a lack of iron as a common element might influence our biology as well...Iron is the primary component of blood that creates it's red color when exposed to air, with a strong lack of iron it's quite possible the creatures inhabiting this planet would bleed a different color. Or is this in the context of just neglecting metallurgy even when the minerals exist?

For my specific question it's a case of lacking metallurgy even though the metals exist, but that's an interesting point.

Lack of heat isn't going to be sufficient: to melt and even smelt copper and iron, all you need is wood and one of several ways to make bricks and/or mortar. Frankly if you can make glass, you've got what you need to get going on metallurgy.

You should read Greg Egan's The Clockwork Rocket. It takes place in a universe where the laws of physics are very different from ours and, among other things, there don't seem to be any metals. Definitely no electrical technology.

Carbon nanotubes are stronger than steel, conducts electricity well, and are lightweight. It might be possible to create advanced electronics without metals from carbon nanotubes based materials.

Note that up to the 19th century, even rural Europe used almost no metal. The common peasants did manage to do a lot of things without metal, I've seen a water mill with absolutely no metal parts, almost 200 years old, still in working condition. Metal was very expensive for peasants to buy, so except a knife or two and maybe an axe (and a plough if they were really really rich), a peasant household didn't have much (or any) metal available.

@vsz How did the no-metal-parts water wheel cope with the problem discussed in part 1 of Ifree Contractor's answer?

@TimB : I'm not an expert, but I heard that there are types of wood which are hard enough to be used for axles, especially if prepared well. Also, a water mill does not have a very fast speed, and might not be on all the time, only when needed.

@TimB: hypothetically, stone or ceramic could be used for half of the interface (wood axle in a stone bushing). Wax on the wood might help to reduce friction. The main problem with both of those is heat: stone and ceramic are terrible heat conductors (heat & electrical conductivity often go hand-in-hand; all those free electrons), so wouldn't dissipate heat, and wax might melt and flow off. Water works well as a coolant & lubricant (especially on stone & tile); a water mill would have a steady supply (though the actual mill probably didn't use water that way).

@CAgrippa, Maria Lin: further to CAgrippa's comments, tin and lead can be smelted at campfire temperatures, and thus are easily discovered by accident. Tin and lead are softer than gold and generally comparable or weaker in strength; gold is the most useful of the three on their own (tin is quite useful in alloys when another metal makes up the bulk). Are you terribly concerned with the "why" of the lack of metal working? I suppose there's always "God(s) did it", if your world has such beings present (then you get to go into the psychology of gods, which can be fun).

Nova's "Making Stuff: Stronger" starts with steel, but goes on to cover a number of non-metallic materials and should provide all manner of ideas.

@outis, My why is already set, for the most part. My primary concern was including things that might have been impossible or unlikely without the use of metal. I'm glad the conversation has gone a bit beyond that though, as it's given me more to consider.