Dear Experts,
I used Topaz to identify mineralogy in XRD and I found that the Muscovite and Illite peak is almost same each other.
If the sample consist of low Illite/Muscovite content, it will be hard to difference both of them.
How do you difference Muscovite and Illite?
Thank you very much
Thank you very much Mr. Song
Yes Usually I do that for Clay analysis but what can we do in Bulk analysis?
It is a difficult task and generally not required to distinguish between muscovite and illite as illite is a clay size mineral with low K content and more water than muscovite.
The difficulty you face is to some degree related to the often general nature of the definition of illite that is in common use ...mica like clay size consitituent....and the other frequent use which is to label a peak near 10 angstroms in a diffraction patterns of a clay size fraction 'illite'. In reality the 10 angstrom peak and mineral group it represents in many sediments, rocks and soils is a heterogenous mixture of micaceous minerals. So your 'illite' may often include some micaceous components that could also be classified as muscovite if we have some means to determine their characteristics. In practical terms in a bulk sample where I assume you are looking at random powder XRD data, you might try to make a distinction bassed on polytype, e.g. a true muscovite will likley be a 2M1 polytype, whereras illites are usually 1 layer polytypes often with various degrees of dissorder. However, it is not a trivial matter to try to include models for illite structures in Rietveld codes.
Dear Stephen Hillier
Thank you so much for your explanation.
I agree that sedimentary sample consists of heterogeneous minerals and of course high probability of Mica.
The problem is the percentage between Illite and Muscovite as most of the peak overlap each other.
The sample is Core sample from drilling where I am looking for the Clay minerals which fill the void and the percentage of it. I identify the Illite and Mica.
When we get Illite with high Mica it will be a question because Mica comes from primary mineral or metamorphic minerals furthermore it will be making a bias in rock identification and no good for the permeability.
Moreover, we also prepared the sample in thin section and it shows that the sample only consist of low Mica more Clay and it is more convincing.
And usually I used Muscovite 1M.
Thank you and have a great day!
- Badges
- Science method
- Similar topics
- Methodology
- Crystallography
- X-ray Diffraction