Producing MYSTIC topaz gem colour effect.

Hi guys

First let me say I’m fairly new to blender and I’ve only done some minor projects other than the tutorials just to get a bit of variety in my practice.

I’m doing a jewelry and gemstone project. While looking for source material I came across a “Mystic” topaz. For those that don’t know Topaz can come in pretty much any colour. What intrigued me about the mystic variety is it goes through the entire rainbow of colours depending on how the light hits it.

I was wondering if this is even possible to reproduce in Blender and if so how would I do it. At first I wanted to do some simple gems as practice but after seeing this I’m feeling a little inspired so it will be dissapointing if it cant be done.

If you have never seen mystic topaz check out the link and image below.

did you look at blendswap there are several gem models!

happy cycles

I must admit some of thats a little hard to follow given how much I’ve done so far but I’ll have a good read and report back if I need clarification

Yes I’ve looked there. Plenty of gems. But I can’t see anything that changes colour with the angle light hits it. Not really sure what to search for though

if you have not found it on blendswap
don’t think you can get these type of reflections in cycles yet

try with luxrender which have more options for these reflections type

u don’t remember something like that for gem
I ll check out some refractions but not certain it can be done in cycles

can you upload the gem shape for testing
may be with some refractions it might be possible

happy cycles

hmmmm - are my posts invisible or something. I just knocked this up using exactly the techniques I described above. Looks like a pretty reasonable approximation of the photo in the OP.

first pic have a lot more colors !

I found one on blendswap that has a lot more did u see that one

\but even that don’t really look as clear and sharp as first pic!

happy cycles

That blendswap has gems showing dispersion. The gems are a single colour with dispersion simulated by splitting the RGB components of the gems and passing them through different IOR values. Thats not what the OP is asking for.

Some gems like mystic topaz exhibit a colour change effect which depends on the viewing angle (almost like iridescence). To simulate that you have to pass a different colours through a Fresnel or Layer Weight node.

OP - try downloading that blendswap file for your gem model/mesh - but apply the following node setup to it instead of the one supplied - it should get you pretty close (this is what I used in post #7)

Of course - you could ultimately go one further and try to combine both techniques (colour change and dispersion).

I cant find a great video to demo it but here this might help. Its had to show with still images.

I’m planning to use it for an animation, not a still image so getting it to change with the angle of the light is the idea.

I will admit I think this is beyond my current skill level but when I discovered it I thought screw it lets see what I can do (With you guys help of course)

heres the best I can find so far

I think we need the model here

not certain if there is one or 2 gems in first pic or how many faces!

but agree looks more like refraction effect plus something else

happy cycles

No Moony your posts are not invisible. The thread you linked to was what I meant when I said I don’t follow all of it. I’ve not used Cycles yet.

Part of the reason I decided to do this is because I don’t have any idea how. Learning and all that


can you provide the mesh object so we can test it with right shape!
might get better results

I got an example with irrisdescence
but have to find it !

thanks (75.6 KB)

Ok I got the gem shape from this file. Its its the one called “Gem”. I’ve currently got no texture or material set on it.

Here is the node setup in post #9 animated.

Thats is some quick work with the animation. I’m having to rely on CPU rendering at the moment. Somehting like that takes me ages.

looking at first pic I see colors coming from the inside faces inside the gem not from the outside faces

strange effect !


I’m not even sure its from the inside faces, I think it just looks like that. I did think it was a weird effect though, thats why I like it

you model need some top faces normal correction and was done in blender not cycles!


Mystic Topaz is produced by coating the gem with an iridescent coat. Part of the colour you see will be from the surface of the gem (in much the same way as a soap bubble produces colour), part refraction/dispersion of the surface colours through the gem and part from reflection off the back faces.

It would be very difficult to reproduce a physically accurate representation of this effect, so you have to try and replicate the effect using techniques that are available.

The example I gave above is only a rough starting point. Perhaps look up materials that simulate the iridescent effect of soap bubbles (there are a couple around on these boards) and combine these with dispersive glass/gem materials (also available on these boards). You’ll learn a great deal about cycles by studying and tweaking these materials.

did a test with refraction and get some nice colors but far away from the first pic!

will think about it tomorrow might get lucky and get something