forum Anyone know anything about gems?
Started by @Purple-Cat location_cityThe Worldbuilder

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@Purple-Cat location_cityThe Worldbuilder

I want to make up a few original gems for my world but I'm not sure what properties to think about. I already have a list of a few things I found online but it either feels incomplete or confusing.

I have things like hardness, cleavage, fracture, luster/shine, clarity (which I'm still trying to understand) rarity and colour. Two that I don't fully understand is refractive index and dispersion and I'm not sure how relevant they would be to creating a new gemstone.

My goal is to have some gemstones for jewellery or magical purposes like charms and amulets and spell ingredients, that sort of thing.


I'm no expert but I do know a fair share of things! My grandparents were goldsmiths, they worked with gemstones too so I know some bits. Do you have any specific questions?
The refractive index is tied to the density of the medium, and it stands for how much the path of light is relocated by the medium. Say you shine a flashlight at a 45 degree angle on the surface of water, due to it being more dense than air, the light will follow a more "downwards" path, as if it made this shape:
…..\ ………….

This here exemplifies. See how the glass changed the path of the light? That's some refraction for you.

With gemstones it's no different. Each gem relocates the light in slightly different rates. How does that matter, you may ask? Well, have you ever noticed each gemstone has a "classic" cut? Like how some are "diamond" shaped, some are square shaped, some are polished to resemble a teardrop? Usually, that "classic" or default cut is the one that allows the refraction to revert the biggest amount of light, so its the one that makes the gem shine the brightest when polished. The most common is the round cut, it allows nearly 100% of the light to be reflected. It's the typical shape you think when someone says "diamond". Fun fact: in portuguese, this cut is called "brilhante" (literally translated to "shiny") and most people think brilhante is a whole other separate gem, when it's actually just a cut shape and any gem can be turned into a brilhante! My own grandma thought this, even after years of working in the industry lmao, this is how common (yet incorrect) knowledge this is.

This is the shape! It take advantage of refraction and reflection to make even transparent gems like diamonds look so shiny they seem opaque.

Something I reccomend taking a look into is:

  • gems that can't be left in the sun (color fades, makes them brittle, a good rule of thumb is most gems made of quartz or that aren't opaque. Orange ones can go in the sun tho!). These wouldn't be very useful as part of obelisks or statues, and questionably, could be used as amulets as long as they don't spend much time under the sun.
  • gems that can't get wet (they can soak up water and dissolve with time! A good rule of thumb is all gems that end with "ite"). That could tie to being used as ingredients, if they have to get wet, you can either make it so that they dissolve completely (as if you dissolved a sugar crystal in coffee) or you could make them not work at all for that very reason, Idk, you could make some parallel!

I don't believe in crystals' magical/spiritual properties, so unfortunately, I can't help with that other than some few meanings (example, rose quartz and jasper manifest love, citrine is confidence, etc.). Some gems also have ties to certain academic fields, since, at least in country, when you finish university you get a ring with a certain gemstone, depending on the major yu just finished, you can search these up and use as inspiration as to how a gemstone tied to that academic field tends to look, that can tie to what magical properties your custom gems can have.

So, if you have any other questions, don't hesitate on asking me! I don't know everything or much at all, but I'll try to help as I can.
Good morning/day/afternoon/evening/night, happy writing, God bless you and stay safe! |-/

@EldritchHorror-Davadio health_and_safety emoji_events

Other things to think about in terms of gemstones are availability and method of formation. Different gems form from different processes. Diamonds famously require extreme heat and pressure applied to carbon, as opposed to Emeralds, which form in underground bodies of water. Similarly, rubies and sapphires are the same material (Corundum) formed generally the same way, but with different minor ingredients which give them their colors. Many gems can be "lab-grown", while some are so rare there are only a few specimens in existence. Pearls are produced by living creatures, so maybe there's a critter that produces gems with magical properties? Maybe some gems can be grown or manufactured easily, so they make good ingredients, or a lot of people have the powers they grant. Maybe rarity can correspond to higher ability to generate magic, or better potency. Some gems are known to change colors depending on light, such as Alexandrite. If color affects ability, maybe a gem could grant different effects in sunlight and moonlight. Perhaps some gems could have abilities when crushed or destroyed, like providing an explosion or emitting a vapor (similar to shattering Prince Rupert's Drops or using acid on pearls). Some gems change color set in certain metals; if color corresponds to powers, maybe the same gem used in different ways gives different results. Just some ideas, probably stuff you already know, but maybe your creative mind has been inspired :)


Similarly, rubies and sapphires are the same material (Corundum) formed generally the same way, but with different minor ingredients which give them their colors.

YES THIS!!! AND CRYSTALINE FORMATIONS TOO! Selenite and Desert roses are the exact same gem, but selenites' crystals are allowed to grow naturally, while a Desert Rose's crystals grow in disordered positions, due to grains of sand getting in the way and altering the direction of the gem's growth.

A desert rose

and a selenite! They're the exact same crystal, just grown different!

And as a continuation of my previous comment and the person's above, some stones contain metals in their composition, so they can rust overtime and in contact with water, such as hematite. Some crystals can be craftted through other ones, for example:

  • Agates can be dyed to create several different colors. Same for zircons, it's cost effective and they look a lot like other gems, so most gems in the market are dyed zircons!
  • Citrines can both be found naturally or created through amethysts! These 2 gems are the same, but generated under different temperatures. Heat treated amethysts are considered citrines, and to identify it's simple: natural citrines are always 100% yellow, while heat treated citrines can have white quartz along with the classic translucent yellow, just like amethysts have white quartz along with the purple.
  • Opals can be synthetic, but it's a hard process. The way out of this is Opalite, it's a very common, 100% sinthetic opal look-alike made of colored glass. Opalites are commonly refered to as "moonstones" but moonstones are another entirely different gem! Many gems on the market end up being glass fakes, so you could have a dicey merchant who sells those look-alikes in the story and it fucks up the spells maybe? Or synthetic gems don't have any powers, maybe?

From left to right: Opal (natural), Opalite/"moonstone" (synthetic), Moonstone (natural)

  • Some gems aren't gems at all! Goldstone and blue goldstone (often refered to as sunstone and nightstone, but sunstone is a different and natural gem) are nothing but glass and metal powder, that gives them their opaque complexion and glittery shimmer! I have some, they're very brittle :/

    here they are!

I'll add more later!

@EldritchHorror-Davadio health_and_safety emoji_events

Many gems on the market end up being glass fakes, so you could have a dicey merchant who sells those look-alikes in the story and it fucks up the spells maybe? Or synthetic gems don't have any powers, maybe?

Ooo, or maybe, gems with high potency are expensive, but there are "generic" versions of the gem, kinda like diamond and moissanite. Similar hardness, similar coloration and sparkle, used in similar ways, but moissanite is much, much cheaper. So maybe "generic" versions have defects or have weaker effects or something?

@The-Magician group

@TheColourfulCraftyGemstone If you need to know anything about the availability, toxicity and/or metaphysical properties of any crystal to inspire the ones you want to create in your world, please don’t hesitate to dm me! I’m a 7 year practicing witch who’s also doing a Geology Diploma, so if you need any sort of resource I’m very happy to provide

@Purple-Cat location_cityThe Worldbuilder

This is all so cool! Thank you all, this has defiantly cleared somethings up!

@Davadio I love the animal making it’s own gemstone idea! I’m focusing a lot on animals and resources at the moment so this is a great idea.

@Wykie The merchent selling synthetic lookalike gems is also a great idea! Perfect for stealing and replacing valued artifacts.

I never thought about how some forms of glass could also be considered gemstones. I’ve heard about glass gems replacing the real versions in jewellery but I never thought sunstone to be glass, though now that I do it seems so obvious when you look at one.

The thing about Dessert rose and selenite is also interesting, a gem with the same properties but is considered two different gems because of how/where they formed? So cool! I also have a selenite crystal, very pretty.

Would any of you happen to know a few things about metals too? Seeing all this new information about gems is making me think I’ve been doing metals the wrong way. See, I tend to roll certain dice at random to get a level for each property, it makes it easier to create things quickly and doing it at random opens other things for me to explore in world that I wouldn’t think of otherwise and I want to do the same with gems. But now I’m not sure how many properties depend on other properties in metals. Like brittleness and hardness, sometimes I get drastically different numbers for each and I’m not sure if they depend on each other, are the same thing or are two different concepts, same goes for malleability and ductility.

I’m not too fussed on how metal and gems are naturally formed (mostly because it seems a bit complicated and hard to do quickly, with chemicals and ground depth and heat temperatures ect)

@The-Magician group

Most metallic ore deposits are a result of plate tectonic activity. High heat flows and convection currents at divergent plate boundaries, such as midoceanic ridges, create submarine hot springs called “black smokers” that deposit solid masses of metallic minerals.

(Typical) Properties of metals include:

  • high melting points
  • good conductors of electricity
  • good conductors of heat
  • high density— It’s important to note that for the most part, a substance with a high density also has a high mass for its size.
  • malleable (can be beaten into sheets)
  • ductile (can be drawn out into thin wires)

(Atypical) Property examples:

  • Mercury has a low melting point and exists as a liquid at room temperature
  • Elements in group 1 of the Periodic Table have low melting points, but also low densities, for example, sodium is less dense than water and so it floats

The properties of metals—as well as of elements in the other classes—depend mainly on the number and arrangement of their electrons.

@EldritchHorror-Davadio health_and_safety emoji_events

Brittleness and hardness do not necessarily depend on each other, and getting wildly different numbers is ok. For instance, diamond is the hardest material, but a diamond sword would shatter on the first swing because it's incredibly brittle (Sorry Minecraft). The same can be true for metals. A metal may be very hard, meaning it is scratch/mark resistant, and can't be easily cut, but hardness doesn't equal strength. The same molecular bond that makes the material hard, may also make it inflexible, and therefore super brittle. This is why the most durable weapons/tools/artifacts are not necessarily made of the hardest materials.
Some metals, like pure gold, are soft enough to be scratched with your fingernail. Some metals, such as titanium, are incredibly hard but much lighter than you would expect. Some metals, like lead, are soft but incredibly dense and heavy. Some metals, like copper, are particularly excellent at conducting electricity. These different properties could be turned to add magical features. For instance, maybe gold is used to craft magical items under time restrictions, because it's easy to shape. Maybe copper makes excellent amulets or wands because it's an excellent magic conductor as well as electricity.
Metals also have the ability to mix to form alloys. You don't really find gem alloys, but with metals you can mix them to get the properties of other metals (sorta). For instance, steel is an alloy of iron and carbon, making it stronger, harder, more receptive to tempering, and generally just higher quality than say, pure iron. Other alloys include brass (copper+zinc), bronze (copper+tin), stainless steel (iron+chromium+nickel), solder (lead+tin), and electrum (silver+gold, often used in ancient coins). Another interesting fact is that some alloys occur naturally, like meteoric iron (which is a meteor with mixed iron and nickel). So maybe if some of your metals have magical properties, mixing them to form alloys can merge the magic, creating new powers, or strengthening existing ones.
The other side of both of these ideas (gems and metal) are the people who specialize in them. Gem cutters, jewelers, blacksmiths, and miners would all need to be highly skilled in magic. Which makes for an interesting dynamic. Just some thoughts :)

@Purple-Cat location_cityThe Worldbuilder

Does anyone know much about where gems tend to form?

I’m trying to look up different places gems can form and it is only telling me how they form or what countries they form. I know about how some gems can form near/underwater, under pressure and from living things (like pearls) and I want to play around with other ideas, like gems forming on the surface/above ground or in extreme cold instead of heat, or from plants (but that one would be entirely fantasy based). I just want to find out if anything like that would really be possible.

@EldritchHorror-Davadio health_and_safety emoji_events

Well, ice is crystalline, similar to gems. So you could have a material that once frozen into ice will stay crystalline, even in heat. Or, you could have a form of magma that, if it dries normally, just forms rock, but if it cools rapidly, it forms gems of some kind.
You've mentioned water. Think about how stalagmites form: constant dripping of mineral laden water. You could have something like that on the surface, maybe water dripping from trees, or the mist of a nearby waterfall, or something, where the water slowly forms stalagmites- but gem stalagmites instead of rock ones.
You could also have plants form gems by how they decay. If they die in the wild, nothing happens, but if a magic user or an apothecary dries them out, they harden, and can be polished into gems. Or something.
Plants do form coal, eventually, which is a form of carbon, so it's not Totally fantasy to think they could form other minerals.