I was wondering about how to figure out the geology of your fantasy world. For example, where would granite, limestone, sandstone, and gems (diamonds, amethyst, etc.) be placed? If a castle is made from a particular kind of stone, it should be relatively easy to obtain and transport -- in other words, close at hand to where the castle is built. If a character is hiking in the wild and finds a gemstone, it should make sense that it would be there. I would like to have a karst landscape, like the area where I live in the real world, in one area of my fantasy world, but I am not sure if there are rules for where that would be placed beyond the presence of water and limestone. My question is, can someone point me to resources for figuring stuff like that out?

  • $\begingroup$ i can point you a direction... Taj Mahal in India $\endgroup$
    – user6760
    Mar 5 at 3:38
  • $\begingroup$ If a character is hiking in the wild and finds a gemstone, it should make sense that it would be there. Why? The habit of so many new authors is to make things "as realistic as possible," but the point of a good fantasy story is for the world's rules to be consistent, not based on science. Most people wouldn't know why sapphire was located where it was, but that wouldn't ruin the story at all. $\endgroup$
    – JBH
    Mar 5 at 15:48
  • $\begingroup$ @JBH Thank you. You're right. I had gotten so focused on making things realistic that I forgot that fantasy worlds are ... fantasy. So I don't need to focus so much on where to put gems realistically. But a karst landscape on the other hand.... $\endgroup$
    – user109520
    Mar 5 at 19:21

1 Answer 1


On Earth Not Quite as it is on Yeola

The obvious answer is, obviously, where these things are located on Earth. I may be wrong but it seems like you're trying to map out a geological sibling to Earth here. An Earthlike planet. If that's true, then really your very best resource will be a college level geology text book.

Not all planets are Earthlike, even those that might look Earthlike from high above, or even on the surface. For some, the geology text is still a good resource, because you'll get a good foundation in the geochemistry and planetary evolution, tectonics and the like.

We do have a Worldbuilding List of Resources that doesn't necessarily list geology text books, but might provide you some interesting avenues to pursue!


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