Why Mica is a Must


There are a few mineral-based ingredients that even hard-core, plant-based-ingredient-loving people like me will happily include on the list of 'exceptions to the plant-based rule'. One of these is mica. Mica is quite simply a must-have.

You: how can some rock be a must-have?
Me: Think eyeshadow.

Are you with me now?

Good! Because today we're celebrating mica and all of its fabulous versatility!


Glittery Crumbs

The word mica is derived from Latin and means 'a crumb'. The name is also so similar to the word micare (which means 'to glitter') that you can't help thinking they're somehow related.

Muscovite - also known as common mica

Mica – The Group

The mica group actually encompasses 37 minerals – all with a layered, sheet-like, or plate-like texture and a slew of impressive properties, like:

  • elastic 
  • flexible 
  • resilient 
  • hydrophilic (capable of interacting with water) 
  • refractive (throws light around in a shiny, lovely, colorful way) 
  • reflective 
  • ranges in opacity from transparent to opaque 

There's actually much more, but I was afraid you might think I was exaggerating. 

I'm not.

Really.

Preparing For Use

Depending on the desired end use, mica is treated in different ways, for example:
Dry-ground mica will be used as filler in gypsum sheets for drywall, in drilling fluids, as an additive in rubber, as a component of roof shingles, in heat shields, and much more.

Wet-ground mica is, among other things, used for pearlescent paints, as an insulator in concrete blocks, as a durability-increasing additive to axel grease, or  – here comes the fun part – in lipstick, nail polish, blush, foundation, and eyeshadow.



Pearlized, Shiny, Opaque, or Translucent


Depending on the size of the mica particles (and any added coating), the shine-factor will be more reflective and transparent, or more opaque and less lustrous.

One wouldn't think it possible to coat tiny flakes of mica, but this is exactly what is done to mica used for pearlized make-up colors. The coating is often a metal oxide (for example iron oxide or titanium dioxide). By combining different metal oxides and adjusting the thickness of coated layer, a wide range of pearlescent pigments can be created.

In short, just about every make-up color you find includes mica in one form or another.

Is it Safe?

Yes. It's safe. Find more info at this page ar CosmeticsInfo.org as well as this page at CosmeticsInfo.org. And here is a link to an FDA chart with list of color additives permitted for use in cosmetics.



Size Matters

For an overview on mica particle sizes, check this info (from DIY Cosmetics)

COLOR EFFECT vs. PARTICLE SIZE

Particle Size 15 µm or less = low luster, good hiding power
Particle Size 2-25 µm = silky luster and strong hiding powder
Particle Size 10-60 µm = pearl luster with medium hiding power
Particle Size 10-125 µm = shimmering luster and low hiding power
Particle Size 20-150 µm = sparkling luster and transparent
Particle Size 45-500 µm = glittering luster and very transparent

Comments

Anonymous said…
This is interesting review - mixing make-up, good health, and geology all together. The various mica minerals have all sorts of interesting properties as briefly discussed above. I enjoyed reading this a lot!...about the Micas!
Lise M Andersen said…
Thank you Anon. This was a fun post to write, I found so much interesting material that it was difficult to decide what to cut and what to keep.
Carol said…
Hi Lisa, I have learned so much from you and really appreciate your blog/site! (Found you from following POI - love her blog too). I am curious your thoughts on sourcing mica and how you determine the highest quality? My understanding is that "coal tar color" must be batch tested for heavy metal levels and purity and therefore certified before hitting the market (source - a consumers dictionary of cosmetic ingredients - pg167). I understand coal tar colors are not the same as micas, but just trying to see if micas are regulated the same. On the cosmeticsinfo.com site (under Mica - overview) it says "the levels of heavy metals in Mica are regulated by the FDA, and the small amounts that may eventually be in cosmetic or personal care products do not pose a risk to human health". But on the safety page it says "the Food and Drug Administration (FDA) lists Mica as a color additive EXEMPT from certification". I'm confused, FDA says it is safe, but then doesn't require certification. My question is - does mica get batch tested for heavy metal levels and purity or not? Do you have a supplier that you trust for purity and heavy metals? Thank you so much for your time!
Lise M Andersen said…
hey there Carol - thanks so much for your kind words. You and I are both huge fans of Susans blog!

Your question is very timely, as I am working on a bit of research into the use of metals and minerals in make-up and plan on doing a post on this before long (don't take that literally-- sometime 'before long' turns out to be a year if that's where the research takes me)-

Meantime, I can recommend DIY cosmetics as a reliable source of both product- but also information.


But- to give you a bit of an immediate reply - I checked the FDA page - which says micas are exempt but still must comply when used in cosmetics---

Quote:
"Colors exempt from certification. These color additives are obtained primarily from mineral, plant, or animal sources. They are not subject to batch certification requirements. However, they still are considered artificial colors, and when used in cosmetics or other FDA-regulated products, they must comply with the identity, specifications, uses, restrictions, and labeling requirements stated in the regulations [21 CFR 73]."


Find the page here
http://www.fda.gov/ForIndustry/ColorAdditives/ColorAdditivesinSpecificProducts/InCosmetics/ucm110032.htm


I hope this was of some help!

Carol said…
Thank you for your response, Lisa. Definitely helpful. I just ran across this information on a soap making post explaining the differences between pigments (oxides, ultramarines), fd&c colorants, micas, and herbal colorants - seems to mirror the FDA info. Although she explains that "micas are the individual mica (which looks like a platelet) is coated with FD&C colorants, or pigments, or a combination of both to achieve the colorant." http://teachsoap.com/2012/03/24/soap-coloring-options/ I would love to use micas, but still unsure since they are mined and untested for purity, and if this resource is correct they are coated with synthetic pigments. Right now I am using herbal colorants and straining but I lose about 30% oil doing so and it is such a messy process. Anyway, thanks for all you do. I'll be interested to hear more "before long". =0) I get that and am amazed how much content you get out in the mist of making products. All the best!
Lise M Andersen said…
Hi Carol - thanks for the link and info. There is a difference between requirements for micas used for cosmetics (make-up) and personal care products such as soap. If you check DIY Cosmetics site, you will find information about this. I'm going to bump this up on my priority list -because now you have me all curious! Thanks for the inspiration!