Cosmetic Oxide, Ultramarine Blue and Mica; Bolder Colorants for Soap, But Are They Natural?


August 26, 2012 by thesoapalchemist

Many of us, for a variety of reasons have made a commitment to use only natural colorants in our soaps and cosmetics. We’ve attracted customers who seek out natural alternatives to synthetic content. For them, we artfully use herbal infusions, dried botanicals and clays to show just what can be possible by using natural ingredients, and also how good the resulting products can be.

How do you get brighter colors in natural soap?

When I see flashier colored soaps made by other natural soap crafters it obviously attracts my attention. In my hunt for a brighter blue and a bolder green than my natural options can provide, I’ve emailed a few of these crafters, asking if they’d share what they used for color. The answer I get is always mica, ultramarine blue, or oxide, along with a description of how natural each is.

Cosmetic mineral colorants are synthetic, but “chemically identical” due to safety issues.

Unfortunately, the FDA’s stringent guidelines concerning cosmetic minerals practically require them to be synthetically produced. I looked into the FDA guidelines and discovered that the ingredients needed to make the colorants can be synthetic as well. I decided to ask my suppliers about the “naturalness” of their mineral colorants, hoping perhaps they were at least lab created using natural ingredients. Each responded via email, explaining that while “chemically identical,” the FDA requires cosmetic mineral colorants to be synthetic for safety reasons. Synthesizing these colorants in the controlled environment of a laboratory eliminates problems with impurities and heavy metal contamination. Synthesis is also relatively inexpensive compared to the high cost of purifying naturally obtained minerals. And, mineral colorants that are particularly rare in nature can be made in abundance synthetically (similar to the reasons for making synthetic sandalwood (endangered!) and jasmine ($1900/lb!!) fragrance oils).

Should you be told if the diamond you’re purchasing is a lab created, “chemically equivalent” cultured diamond or a naturally occurring diamond?

The suppliers all stated that the synthesized pigments were “chemically identical” to what’s found in nature. That’s true. And the heightened safety of the product is a wonderful benefit. However, “chemically identical to natural,” doesn’t mean “natural.” Cultured diamonds are chemically identical to natural diamonds, yet they are simply not the gift from nature that natural diamonds are. I would be outraged to discover the natural diamond I purchased was in fact a synthetic diamond. Likewise, marketing soaps as “natural” when they are colored with ingredients having synthetic components, is simply dishonest.  

Here are some resources you might find interesting, regarding the manufactured nature of these minerals.

Iron Oxides; including Yellow, Orange, Red, Brown, Black

The FDA regulations specify “synthetically prepared oxides” and not simply “oxides” as colorants. Further, an explanation is given as to how the synthetically prepared oxides are to be created, stating that the ingredients can be from either natural or synthetic sources. The colorants are exempt from certification, but NOT exempt from regulation. Iron oxides must meet FDA standards to be used in cosmetics.

Source: FDA 21CFR73.2250 specifies “Synthetically Prepared Oxides”

Ultramarine Blue Oxide:

The FDA color additive regulations specify that “The color additive ultramarine blue is a blue pigment obtained by calcining a mixture of kaolin, sulfur, sodium carbonate, and carbon at temperatures above 700 deg. C. Sodium sulfate and silica may also be incorporated in the mixture in order to vary the shade.” Ultramarine blue oxide is also exempt from certification, but it is not exempt from regulation. The FDA regulations outline how the regulated color is synthetically produced (as opposed to naturally occurring), but does not specify whether natural or non-natural raw ingredients can be used. Synthetic versions of all the ingredients listed are available. Was your Ultramarine Blue Oxide made with the synthetics, or the naturals? Can your supplier tell you? If you don’t know, is it right to use it and call your product “all natural?”

Source: FDA 21CFR73.50,

Chromium Green (Chrome III Oxide, Viridian), and also Chromium Cobalt Aluminum Oxide

Due to the rarity and expense of naturally occurring chromium, synthetically produced hydrated chromium oxide is the form in general use as a pigment. A similar colorant, Hydrated Chromium Green, is lab created from naturally occurring ingredients., FDA 21CFR73.2326. Another similar colorant, Chromium Cobalt Aluminum Oxide is a blue-green pigment approved for use in drugs, and can be created from naturally occurring or synthetically produced ingredients. See FDA 21CFR73.1015. SO, is your “Chromium Green Oxide” the synthetically made of synthetic ingredients Chromium Green, or the “Hydrated Chromium Green,” which contains natural raw ingredients but is synthetically made, or is it “Chromium Cobalt Aluminum Oxide,” which could have been made from all natural ingredients or maybe not? Does your supplier know? How natural is your “natural green oxide?”

Mica and Mica-based Pearlescent Pigment

See FDA  21CFR73.2496 (cosmetic mica) and FDA 21CFR73.1496 (Mica) and FDA  21CFR73.1350 (mica-based pearlescent pigment). Mica-based pigments are exempt from certification, but not exempt from regulation.

White powdered mica is obtained from a naturally occurring mineral called Muscovite Mica. However, the colorful mica “pigment powders” approved for cosmetic use are lab created using either naturally occurring or synthetic ingredients by “depositing titanium salts onto mica, followed by heating to produce titanium dioxide on mica.” Do you know if your mica pigments were made from natural raw ingredients, or with chemically equivalent synthetic ones? If you don’t know, is it right to use them and call your product “natural?”

With my chemistry background, and belief that through science, our world is a better, safer place, I am hardly the person to put down lab created materials or products. Synthetic does not equal bad, nor does natural equal safe. However, I market my soaps as being colored “naturally.” Since the synthetic content of “chemically equivalent” cosmetic minerals is unknown or not disclosed, I will not use Ultramarines, Oxides or Mica’s in my “naturally” colored soaps.


9 thoughts on “Cosmetic Oxide, Ultramarine Blue and Mica; Bolder Colorants for Soap, But Are They Natural?

  1. says:

    Can I say Ewwww Gross and thanks so much for making YOUR soaps. I LOVE U AND YOUR SOAP!

  2. Antony says:

    Thanks for the article – always good to see fellow soap makers share! I would like to temper the argument a little though because many people do seem to educate that ‘natural’ is best which gives the impression that all natural ingredients are ‘skin safe’ and unproblematical which simply isn’t the case. ‘Natural’ doesn’t necessarily mean ‘good for the skin’ and indeed there are plenty of natural/botanical ingredients that ardent natural soap makers find indispensable that contain known allergens and skin irritants. From humble Lavender Oil containing the allergens geraniol, limonene and linalool to Wintergreen oil containing Methyl Salicylate which can have a profound physiological effect on some people – esp. those taking prescribed anti-coagulation medicines. Certain colourants, synthetically produced though they may be, can be more stable and inert on skin when compared with their often less vivacious natural counterparts. Did you know, for example, that Alkana Tinctoria, that beautiful colourant we rely on for Lavender shades in soap making, can irritate the skin if used to colour balms naturally? Just a thought – when all’s said and done everyone’s skin is unique and while we go out of our way to remain true to our natural ‘roots’ occasionally we do have to resort to synthetics. Alas – nature doesn’t ‘do’ a raspberry essential oil…..

    • Thanks for commenting! My intent in writing the post was not to enter into a “natural is better” discussion. I personally have never subscribed to that philosophy; my chemistry degree and love of science prohibit that! I’ve also never marketed my products as such. The point of my article was to point out that things that you might expect to be natural, may not be. I encounter many people selling “Natural Soap” that contains unnatural scent and color ingredients. The people buying the soap are led to believe that those bright colors and interesting scents can be obtained naturally and often want me to duplicate them in my “all natural” soaps. They also believe that what the other soap makers are selling is “all natural” due to the so called “mineral colorants” being used in place of “synthetic colorants.” Often, the soap maker believes the mica/oxide/ultramarine they used to be “natural,” too, because their supplier didn’t tell them any different. They then market their soaps with this misinformation. Some suppliers are unscrupulous, and care only about selling the ingredients. They don’t bother to educate customers about the real source of the ingredient. Some simply don’t know. And others simply assume that a customer who is looking for natural colorants MUST be doing so because they believe them to be more “safe,” and therefore, feel perfectly justified in selling them the synthetic oxides/micas/ultramarines because they are the “safe alternative” to the naturally mined varieties. What these suppliers fail to realize, is that the reasons for wanting a natural colorant may not relate to safety at all, but rather to a desire to simply see what can be made with natural ingredients. Assuming to know the motivation of a customer, in this case, leads to the customer assuming the ingredient is natural when it is not. I feel that full disclosure and transparency of the sources of ingredients on the part of the suppliers would drastically improve our ability as soapmakers to make decisions that satisfy our own particular wants and needs.

  3. Liz-Anna says:

    Thank you for this excellent piece. I was just struggling with this very thing as my soap supplier has stopped carrying some of the natural colours I had been using such as rattanjot for a purple colour and some of the natural clays I had used previously. I ordered some ultramarines and oxides but was struggling with whether or not to use them. Now I think I will but I will change my labelling to simply Handmade soap and dispense with the All Natural label that I used previously..

    • Thanks for your comment, Liz-Anna! I struggled with that decision, too. They’re safe, they’re beautiful– but my soap company is named The “Natural” Bar Soap Co. I didn’t feel right using non-naturals in my recipes. If I do start using them, I’ll market them under a different label to avoid confusion with my truly naturals. Happy soaping! 🙂

  4. Debbie says:

    I came across this while searching for a natural ultramarine pigment …… just to see whether I could find a supplier claiming to have it. And your post touched a nerve, as I’ve seen exactly the same as you – soapers calling their soaps “100% natural”, even though the colors clearly are not natural! Having struggled to achieve various colors in my soaps using only natural coloring agents, I find this really frustrating because consumers are being badly misled and it seems dishonest.
    I agree that natural may not always be better or safer – but I (like you) wouldn’t want a synthetically produced diamond, even if it looks like the real thing!

    • Thank you so much for commenting, Debbie! What frustrates me, is that if I get into a discussion with a supplier about their “natural” pigments not really being natural, they’ll agree (yet do nothing to market the ingredient differently) and quickly attempt to shift the conversation into one about safety. “We can’t offer truly natural oxides because the stuff that comes out of the ground is tainted with heavy metal impurities, blah blah blah.” Exactly! That’s the point. The “natural” oxides aren’t safe and aren’t approved for use in cosmetics by the FDA, so synthetic look a likes are created. Yes they’re safer, but they shouldn’t be marketed as “natural.” Some ideas for natural colors that have eluded me: I had a tricky time with blue and red, especially… Try some Cambrian Clay for blue (it makes a very pretty heathered baby blue after a full gel) and a blend of rose kaolin and moroccan red clay (somewhat terra cotta-ish, but a decent “natural” red). Also, I just started using spinach powder and parsley powder for green, after finding that spirulina (a blue green algae) fades really badly over time. Happy Soaping! 🙂

      • Rebecca says:

        You might try beet root powder for red. Thank you for the suggestions for blue and green. I have both spirulina and spinach powder and now I know which will be best.

      • I have some beet root powder… I should probably try it out! lol. I really loved Spirulina, but was selling soap so fast, I didn’t have them long enough to really notice the fading. When sales of that variety slowed (it was a springy floral), I noticed the color really went beige after 3-4 months. I’ve been using parsley powder lately, and it seems to be lasting about the same as the spirulina, but gives a bit brighter, spring-ier green. Also–I discovered a very nice orange– annatto seed. It has to be ground in a coffee grinder FOREVER to get it smooth and fine, but the color is close to the color of an orange rind- bright orange! It would make a nice fall soap. 🙂 Happy Soaping!

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