Can someone please explain to me (or give a source) how the crystallization diagram of the diopside-wollastonite-silica system looks. I am a new learner of geology and trying to learn ternary systems.

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    $\begingroup$ What is your question exactly? Help us help you $\endgroup$
    – Gimelist
    May 14, 2017 at 8:27
  • $\begingroup$ Sorry, this question is too broad. This is not a text book. What exactly is unclear about it? $\endgroup$
    – Jan Doggen
    May 14, 2017 at 8:43
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    $\begingroup$ can you please explain me (or refer a source) regarding how the crystallization diagram of the diopside-wollastonite-silica system look like. Sorry for the typo above. I am a new learner of geology and trying to learn ternary systems $\endgroup$ May 14, 2017 at 8:47

1 Answer 1


The diopside–wollastonite–silica system ($\ce{CaMgSi2O6-CaSiO3-SiO2}$) was never studied for crystallisation paths in igneous systems. This is not a system encountered in terrestrial magmas, so no one bothered.

However, it was studied as part of a more general lime–magnesia–silica ($\ce{CaO-MgO-SiO2}$) system by material scientists and they came up with this:

enter image description here

Source: Steel Data

You can see small fields for "Diop" and "wolla" slightly above the centre of the diagram. This is not an easy diagram though, and it's of limited use to geologists. If you're studying ternary systems I recommend you go through these instead: Ternary Phase Diagrams

  • $\begingroup$ Thanks for the help Michael. I found a similar diagram in a USGS paper (link - goo.gl/DqP0MY , Pg 53). It appears Ricker and Osborn (1954) studied it but I can't access their article. The reason I am studying it is because it is in my exam syllabus and I have no clue what I am gonna write if this question comes. Of the three systems that I have to study are - An-Ab, Di-An and Di-Wo-Silica , and this last one is giving me tough time. Anyways thanks again. $\endgroup$ May 16, 2017 at 4:07
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    $\begingroup$ I looked at the R&O54 paper and it doesn't add anything more than the diagram I already included in my answer. I am not sure what is written in your syllabus, but a Di-Wo-Silica igneous phase diagram showing crystallisation paths does not exist (unless someone corrects me). It could be a metamorphic chemographic diagram (but still, why not MgO-CaO-SiO2? beats me). Maybe ask your teacher? Or maybe it's a "made up" diagram to see how you deal with the concepts on a new diagram you've never seen before. As long as you know how to work with other diagrams, anything new should be straightforward. $\endgroup$
    – Gimelist
    May 16, 2017 at 5:42

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