Purple clay acting weird in soap

[Elise]

I tried my hand on a secret swirl for the first time. I colored part of my batter with purple clay. I wasn't very good at it, but, most importantly, the clay lost its color during the process ! I was so sad when cutting and discovering the mere shadow of a swirl.

I checked the packaging of my clay; and it is not naturally purple, it is kaolin clay mixed with manganese violet.

At first I thought that maybe this pigment don't do well with lye. But the external parts of the soap kept the color well. Looking at it, I think my soap gelled but didn't gel fully. I can see a slight gel ring. So... did the pigment burn ?

Does anyone had a similar experience ? What do you think happened ?

 

[Mobjack Bay]

I tried my hand on a secret swirl for the first time. I colored part of my batter with purple clay. I wasn't very good at it, but, most importantly, the clay lost its color during the process ! I was so sad when cutting and discovering the mere shadow of a swirl.

I checked the packaging of my clay; and it is not naturally purple, it is kaolin clay mixed with manganese violet.

At first I thought that maybe this pigment don't do well with lye. But the external parts of the soap kept the color well. Looking at it, I think my soap gelled but didn't gel fully. I can see a slight gel ring. So... did the pigment burn ?

Does anyone had a similar experience ? What do you think happened ?

View attachment 76371View attachment 76370

Sorry about the color shift in your soap! According to TKB, manganese violet is not stable in cold process soap (see the details tab, here). I gather from various things I read that it's a pH issue, but I haven't been able to find one clear source on it.

 

[Vicki C]

I have looked at manganese violet before - TKB trading notes that it is “not stable in cold process soap” Manganese Violet
The part on the outside might not have reacted as much with the lye.

 

[Savage Daughter]

I tried my hand on a secret swirl for the first time. I colored part of my batter with purple clay. I wasn't very good at it, but, most importantly, the clay lost its color during the process ! I was so sad when cutting and discovering the mere shadow of a swirl.

I checked the packaging of my clay; and it is not naturally purple, it is kaolin clay mixed with manganese violet.

At first I thought that maybe this pigment don't do well with lye. But the external parts of the soap kept the color well. Looking at it, I think my soap gelled but didn't gel fully. I can see a slight gel ring. So... did the pigment burn ?

Does anyone had a similar experience ? What do you think happened ?

View attachment 76371View attachment 76370

Was it labeled as 'purple Brazilian clay' or anything like that? Or did the label simply state 'purple clay'? And were the ingredients listed on the website you bought it from?

I'm asking because I'm wondering if the seller was knowingly marketing this as authentic 'purple clay' vs synthetically COLORED clay which they knew was *not* authentic 'purple clay'.

 

[Elise]

Sorry about the color shift in your soap! According to TKB, manganese violet is not stable in cold process soap (see the details tab, here). I gather from various things I read that it's a pH issue, but I haven't been able to find one clear source on it

I have looked at manganese violet before - TKB trading notes that it is “not stable in cold process soap” Manganese Violet
The part on the outside might not have reacted as much with the lye.

According to their pictures it might be good to make grey soap . So do you think that the outside part of soaps reacts less with lye than the middle part ? Or is it that it takes more time to react ? The fact that I can see a gel ring made me think that maybe it is a temperature thing...
But anyways... I try to understand out of curiosity but it is clear that I won't use it again in soap... I don't know what I'll do with it.

Was it labeled as 'purple Brazilian clay' or anything like that? Or did the label simply state 'purple clay'? And were the ingredients listed on the website you bought it from?

I'm asking because I'm wondering if the seller was knowingly marketing this as authentic 'purple clay' vs synthetically COLORED clay which they knew was *not* authentic 'purple clay'.

It was just labeled as "purple clay". The ingredients are listed on the website. Someone gifted this to me, I actually only checked the website once I saw the fail. They don't claim it is naturally purple and they state the ingredients clearly. But they don't mention it not being stable in cp soap, which is odd since they do sell soap making materials and they do give information on use in cp soap for other ingredients.
I wonder what to do with this clay... some people seem to use it to create make-up products but I'm not interested in eye-shadow making.

 

[KiwiMoose]

Purples and blues are notoriously difficult to achieve successfully in soap anyway - they often go grey or worse - brown. I recently discovered that my dark purple mica is what's been causing DOS in my soap, and you'll never guess what one of the ingredients in that mica is - yep, manganese violet.

 

[Elise]

Oh no
This was my biggest batch of soap yet, I'd hate to see it go rancid on top of being ugly !

 

[Savage Daughter]

Purples and blues are notoriously difficult to achieve successfully in soap anyway - they often go grey or worse - brown. I recently discovered that my dark purple mica is what's been causing DOS in my soap, and you'll never guess what one of the ingredients in that mica is - yep, manganese violet.

Rhubarb root mixed with indigo gives a beautiful purple. I have seen it done & was stunned at how great it was....I can't remember who did it, unfortunately.

 

[Mobjack Bay]

So do you think that the outside part of soaps reacts less with lye than the middle part ? Or is it that it takes more time to react ? The fact that I can see a gel ring made me think that maybe it is a temperature thing...

Pigment chemistry is so interesting and complicated, but there's not nearly as much online about manganese violet as there is for some other pigments and dyes, or at least not that I've been able to find. I think you should keep at least one bar for long term observation!

Keeping in my that I'm not a chemist, here's what I found. According to one source - "Manganese violet is ammonium manganese-(III) pyrophosphate with the formula of MnNH4P2O7. The pigment is destroyed by strong acids and alkalis. It is resistant to heat up to 250 °C and has excellent stability to light." My web search reminded me that manganese is a transition metal that changes color depending on the oxidation state. See this source - "Like other transition metals, manganese has more than one common oxidation state. The most stable is +2, which is a pale pink color in aqueous solutions. Also important is +4, brown/black, which is found in manganese dioxide; and +7 found in the purple permanganate anion MnO4–. Manganese’s +6 oxidation state is green." Perhaps the manganese in the outer part of your soap is at +2?

 

[Mobjack Bay]

Rhubarb root mixed with indigo gives a beautiful purple. I have seen it done & was stunned at how great it was....I can't remember who did it, unfortunately.

I've achieved nice purples by combining madder and indigo. I extracted the madder pigment using alcohol, which produced strong color, but is time consuming. A soaper named Kandra Churchwell worked with Anne Georges to make an "anti-alkanet' blend for coloring soap using madder powder, indigo and activated charcoal.

 

[Elise]

Pigment chemistry is so interesting and complicated, but there's not nearly as much online about manganese violet as there is for some other pigments and dyes, or at least not that I've been able to find. I think you should keep at least one bar for long term observation!

Keeping in my that I'm not a chemist, here's what I found. According to one source - "Manganese violet is ammonium manganese-(III) pyrophosphate with the formula of MnNH4P2O7. The pigment is destroyed by strong acids and alkalis. It is resistant to heat up to 250 °C and has excellent stability to light." My web search reminded me that manganese is a transition metal that changes color depending on the oxidation state. See this source - "Like other transition metals, manganese has more than one common oxidation state. The most stable is +2, which is a pale pink color in aqueous solutions. Also important is +4, brown/black, which is found in manganese dioxide; and +7 found in the purple permanganate anion MnO4–. Manganese’s +6 oxidation state is green." Perhaps the manganese in the outer part of your soap is at +2?

I don't understand what the +2 oxidation state means (1st time I hear about oxydation states), but that rules out burning the pigment. It definitely was in contact with strong alkali
I'll keep at least one bar for sure.

I don't know what to do with the others. Maybe it is time to try rebatching ? But there are EO in this batch, I feel that rebatching will not do them good. I've never rebatched soap.

 

[Mobjack Bay]

@Elise The oxidation state is telling us that a manganese atom can exist with a slight (+2) or stronger (+7) positive charge.

 

[not_ally]

Purples and blues are notoriously difficult to achieve successfully in soap anyway - they often go grey or worse - brown. I recently discovered that my dark purple mica is what's been causing DOS in my soap, and you'll never guess what one of the ingredients in that mica is - yep, manganese violet.

I hope that manganese violet and DOS is not an issue in mica generally, as after seeing this post I did a deepish dive and every single purple mica or violet sold by every supplier I use the most (Nurture, Mad Micas, Micas and More, Soapgoods) contains manganese violet. Actually, one Mad Micas color, Harold's Purple Crayon, does not list it as an ingredient. It was enough of an outlier that I thought it might be a mistaken omission and just emailed them to check.

I really hope I do not have to start experimenting with natural colorants for purple. I admire those of you who use natural colorants, but the uncertainty that seems like it is part of the process until you are pretty much an expert would make me crazy. ETA: Ok, crazier.

 

[dibbles]

I hope that manganese violet and DOS is not an issue in mica generally

I have been making soap for 9 years now and have used purple micas (mostly from Nurture) a lot during that time. I haven't seen any correlation between DOS and those colorants. I can count on one hand the number of times I've had DOS.

 

[Elise]

I hope that manganese violet and DOS is not an issue in mica generally, as after seeing this post I did a deepish dive and every single purple mica or violet sold by every supplier I use the most (Nurture, Mad Micas, Micas and More, Soapgoods) contains manganese violet. Actually, one Mad Micas color, Harold's Purple Crayon, does not list it as an ingredient. It was enough of an outlier that I thought it might be a mistaken omission and just emailed them to check.

I really hope I do not have to start experimenting with natural colorants for purple. I admire those of you who use natural colorants, but the uncertainty that seems like it is part of the process until you are pretty much an expert would make me crazy. ETA: Ok, crazier.

It would be surprising that soapers wouldn't have noticed that all those micas caused DOS. So I actually feel relieved that I'll probably won't see DOS developing on my soaps (they are already bad enough) thanks to your research !

But seeing how manganese violet react in soap, I wonder what's the point of adding it in micas... Is it just so the powder looks more vibrant and enticing to soapers but once in soap only the other components actually make the soap purple ?

 

[AliOop]

But seeing how manganese violet react in soap, I wonder what's the point of adding it in micas... Is it just so the powder looks more vibrant and enticing to soapers but once in soap only the other components actually make the soap purple ?

People use micas pigmented clays for things other than soap: lotions, scrubs, make-up, masks, etc. .

But I do agree that sellers would be doing everyone a favor if every listing for a mica product that included manganese violet pigment would contain an advisory that it doesn't behave well in soap.

Edits added in bold and strike-out to reflect @Mobjack Bay's great info, below.

 

[Elise]

People use micas for lots of things other than soap: lotions, scrubs, make-up, etc.

But I do agree that sellers would be doing everyone a favor if every listing for a mica that included manganese violet would contain an advisory that it doesn't behave well in soap.

Oups, you're right, there is more than soapmaking in the world !

 

[AliOop]

Oups, you're right, there is more than soapmaking in the world !

Hard to remember that, right??

 

[Mobjack Bay]

But seeing how manganese violet react in soap, I wonder what's the point of adding it in micas... Is it just so the powder looks more vibrant and enticing to soapers but once in soap only the other components actually make the soap purple ?

But I do agree that sellers would be doing everyone a favor if every listing for a mica that included manganese violet would contain an advisory that it doesn't behave well in soap.

Manganese violet pigment powder and mica made with manganese violet as an ingredient are not the same thing. To create the bright colors of lab-created micas, pigment is applied to the mica substrate using heat. (source) In other words, the mica particles are coated with the pigment. With so many of us successfully using micas made with manganese violet for years, I think we can assume that the process used by trusted manufacturers makes manganese violet chemically stable in cold process soap.

 

[AliOop]

Manganese violet pigment powder and mica made with manganese violet as an ingredient are not the same thing. To create the bright colors of lab-created micas, pigment is applied to the mica substrate using heat. (source) In other words, the mica particles are coated with the pigment. With so many of us successfully using micas made with manganese violet for years, I think we can assume that the process used by trusted manufacturers makes manganese violet chemically stable in cold process soap.

Ah-hah! Thank you for the additional information regarding those distinctions. I went back and reread the original post, which confirms that this was not a mica, but a clay with the pigment added. Great info to know!