Mica in Cold Process Soap – Part 1

As someone who has made cold process soap for several years now, I have certainly experienced my share of soap fails. Usually it was because I was unprepared or because I hadn’t looked up how a fragrance oil performs (‘cement’ soap in a bowl is NOT what I generally strive for!) Colours have also been a major sticking point for me in the past. I used to have a real problem getting a nice purple, it would always turn a washed out grey colour – ick! I’m still having issues getting a nice true red using mica, but that’s another topic all together!

These days I’m careful about what colours I use in my soaps, I tend to stick to my tried and true favourites. That way, when I plan on having a beautiful four colour swirl, it turns out as planned with nice distinct colours.

A few months ago we switched to a much better supplier for our micas. So far every mica I’ve tested has been stable in cold process soap, which means they don’t morph (change to an unexpected colour)!

I tested each of our new micas in a basic recipe containing Coconut, Palm, Canola and Pomace Olive Oil but didn’t add any fragrance in case of discolouration issues. I used a ratio of 1/2tsp of mica per 100 grams of soap. So for 1 kilo of soap the usage rate would be 5tsp of mica.

I premixed each mica in a teaspoon of canola oil so that any lumps of powder would be fully dispersed before adding to the soap mix.


One thing to note about using micas as opposed to other colourants such as oxides, is they can speed up trace very slightly. It’s never been an issue as the acceleration is mild, but it is something to be aware of. I tested our Ultramarine Blue and Chromium Green Oxide at the same time as these micas and the oxides didn’t affect the soap mixture consistency at all, even when the mix was left sitting for a while before I poured it into the moulds. Once I added the mica to the soap the mixture went from a thin trace to a thin/medium trace after sitting for a couple of minutes.


Each of the colours are very vibrant after being poured and have stayed true with no colour morphing at all. I haven’t gelled these soaps, they were left to set uncovered on my work bench.

As a side note – I used half the amount of oxide as I did for the mica. Usually oxides produce a very concentrated colour so you don’t need as much for a bright colour. So for the Ultramarine Blue and Chromium Green soaps above I used 1/4tsp oxide per 100 grams.


After 24 hours you can see the colours are still stable. They are losing that shiny sparkly look as they dry, which is completely normal. You can only keep the sparkle from micas when using a clear melt and pour soap base, but as far as the actual colour goes, so far they’re all performing excellently!

I’ll leave these soaps to harden in the silicon moulds for another few days over the weekend. I used a very slow tracing soft recipe so I wouldn’t be rushed when making these test soaps. As a result I need to be patient before un-moulding them so they don’t break apart in the cavity!

I’ll write an update next week after the soaps have been un-moulded and have had a little more curing time.

Stay tuned…

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