Monday, August 10, 2009

Mineral-make up ingredients: Sericite mica

What exactly is sericite mica and why is it used so much in mineral make-up?

Sericite mica is a natural powdered mica (aluminum potassium silicate) similar to white mica with a fine grain size and silky shine. It is used as a talc substitute.

Mineral make-up used to be made with a talc as the primary filler (more about talc soon!), and you'll still find quite a few huge companies using it as the base for foundations and blushes. It has some good features, but it can clog pores, so some people avoid it. So most fillers are considered "talc substitutes". This just means it is good as a large portion of your mineral make-up base.

You can generally buy three types of sericite mica: untreated sericite mica, treated sericite mica with silicones, and treated sericite mica with magnesium myristate. (There are other types, but as I have not used them, I cannot comment on how they feel!)

UNTREATED SERICITE MICA
Untreated sericite mica (usually just called sericite mica, but check with your supplier to see which one they are offering) is colourless and will increase the translucency of your products. It will reflect light, but it tends to be low lustre. It offers low coverage, so it's suitable for light to medium foundations and eye shadows, and it won't clog your pores. It isn't great at absorbing oils, and people with oily skin might find it their colour turns ashy through the day (this is especially an issue for darker skinned women with oily skin!).

Good for light to medium coverage for normal to dry skin.

SUMMARY FOR UNTREATED SERICITE MICA
Usage rate: up to 100% in powdered products.

Whiteness or opacity: To make a colour lighter, to cover up imperfections.
It's a low coverage material, meaning it offers very little opacity or whiteness.

Translucency: The base itself is almost invisible once applied.
This is why we use sericite - it's colourless and increases translucency. Untreated sericite is the most translucent of all the sericites.

Skin protection
Not really applicable with untreated sericite mica.

Slip: The product feels nice going on and staying on.
It offers slip and glide and will feel silky.

Adhesion: The product remains on your skin.
It offers good adhesion.

Absorbency: Your colour will remain true throughout the day and not morph into something due to environmental stresses or skin oils.
It's okay, but not suitable for people with oily skin as the primary ingredient.

Light scattering properties: To give your skin a dewy glow.
Not really with untreated sericite mica.

TREATED SERICITE MICA - TREATED WITH DIMETHICONE
Treated sericite mica - sometimes called dimethicone mica or methicon mica - is treated with dimethicone to increase the water resistance, increase adhesion, and make it more free flowing. It is shinier than the untreated sericite mica, so it will reflect light and reduce fine lines. But it can make some people's skin look even linier, so it's not a product for older skin with deep lines. It will absorb oil to keep your colour true throughout the day, so it's a great choice for people with oily or dark skin. It feels silky smooth on application and on your skin.

Good for medium to full coverage for oily or dark skin as it isn't as translucent as untreated sericite.

SUMMARY FOR DIMETHICONE TREATED SERICITE MICA
Usage rate: Up to 100% in powdered products.

Whiteness or opacity: To make a colour lighter, to cover up imperfections.
It won't make your colours lighter and it's a medium coverage product, so it will cover up some imperfections in your skin.

Translucency: The base itself is almost invisible once applied.
A translucent product that is virtually invisible when you apply it. (Try this on your hand - do you even know it's there?) Not as translucent as untreated sericite mica.

Skin protection
Dimethicone is approved as a barrier ingredient, so it is going to offer some protection from the elements. The sericite itself does not offer protection.

Slip: The product feels nice going on and staying on.
Offers great slip and glide with a silky feeling upon application and on your skin.

Adhesion: The product remains on your skin.
Great adhesion.

Absorbency: Your colour will remain true throughout the day and not morph into something due to environmental stresses or skin oils.
Excellent absorbency and excellent colour retention for people with normal, oily, or darker skin.

Light scattering properties: To give your skin a dewy glow.
Good light scattering properties, but this can make older skin look more wrinkled.

TREATED SERICITE MICA - TREATED WITH MAGNESIUM MYRISTATE
You might remember magnesium myristate as a fatty acid that will offer some lubrication and emolliency to your skin.

Like the other versions of sericite mica, it feels silky on application and on your skin. It is water resistant and helps with adhesion. The added magnesium myristate helps with emolliency: This version of sericite mica will not absorb oils as well as the dimethicone treated mica, but it will impart some moisturization for women with dry skin. As a result, it won't keep the colour as true for women with oily or dark skin.

Good for medium to full coverage for dry skin as it isn't as translucent as untreated sericite.

SUMMARY FOR MAGNESIUM MYRISTATE TREATED SERICITE MICA
Usage rate: Up to 100% in powdered products.

Whiteness or opacity: To make a colour lighter, to cover up imperfections.
It won't make your colours lighter and it's a medium coverage product, so it will cover up some imperfections in your skin.

Translucency: The base itself is almost invisible once applied.
A translucent product that is virtually invisible when you apply it. Not as translucent as untreated sericite mica.

Skin protection
Magnesium myristate is going to offer some emolliency for people with dry skin, but it isn't a protectant as such.

Slip: The product feels nice going on and staying on.
Offers great slip and glide with a silky feeling upon application and on your skin.

Adhesion: The product remains on your skin.
Great adhesion.

Absorbency: Your colour will remain true throughout the day and not morph into something due to environmental stresses or skin oils.
Good absorbency and good colour retention - better than untreated sericite mica, but not as great as dimethicone treated sericite mica.

Light scattering properties: To give your skin a dewy glow.
Good light scattering properties with some shin.

As a note, you can also purchase perfluoroalcohol phosphate treated sericite (PF treated mica) and carnauba treated sericite. The PF treated mica is water, oil, sebum, and sweat resistant and keeps your colours true. (It sounds awesome, but I've never tried it!) Carnuaba treated sericite is water resistant and keeps your colours true.

Sericite mica is readily available in at least one form in most - if not all - mineral make-up supplier's inventory. The untreated version is the least expensive (about $3.00 per ounce) and the carnauba the most expensive (about $6.00 an ounce). These versions of sericite are a great place to start creating a base for any mineral make-up product!

What's the down side of sericite mica? It is going to be heavier when you compare it to something like micronospheres, and you should choose the right one for your skin type. Some people aren't fans of silicones, so the methicon mica is out of the question. (See the carnauba treated sericite above). It is is a lot more expensive than talc, but about the same price as other fillers like Micronaspheres.

And I don't tend to use it without other fillers. It is a great base, but I like to add some zinc oxide or titanium dioxide to make it a little whiter for eye shadow bases, blushes, or foundations, and I like to add some micronaspheres for my oily skin (more about this product shortly). If you have dry skin, the magesium myristate treated sericite mica is great as the base for your foundation without a lot of other ingredients (except perhaps the new powdered oils!!!)

Check out these posts for recipes using sericite mica. You can use the sericite of your choice - I tend to use the treated sericite with dimethicone as I have quite oily skin...


Join me tomorrow for fun with Micronaspheres or Ronaflair M-Spheres or whatever they're calling them these days.

9 comments:

Shan said...

your blog is like a godsent to me! i was just playing around with my micas without any real idea of what i'm doing. could i ask, if i want to vibrant pigmented shadows, it would be better to use more translucent bases? thanks!

Susan Barclay-Nichols said...

Hi Shan! Welcome to the blog! Definitely use the translucent base for anything vibrant, especially if you want to use the colour shifting or Pop micas!

tr3kkie9rl said...

I'm just curious - do you think that sericite is an essential component of mineral powder makeup? Or is it more a personal preference? I'm thinking of making mine with a base of rice powder, kaolin clay, and talc since I have very oily skin. But I don't want a completely matte finish, I would like a little bit more natural look.

tr3kkie9rl said...

How essential do you think sericite is? I have oily skin so I'm thinking of using kaolin clay and rice powder with talc for a base because talc is so much cheaper. Thoughts/comments?

tr3kkie9rl said...

or should I perhaps just skip the talc altogether and use mostly rice powder?

Grace said...

I was making the most hideous eyeshadows! They were draggy and streaky and even painful to apply! That's all changed now that I've found you! I'll never let you go! Lol. Sorry for all the exclamation marks, they were necessary. It was that or type in block :) I am very grateful for your recipes for the eyeshadow bases. Thank you.

Anonymous said...

Why had Treated Sericite in the past have about 1.5% Mineral Oil and now no longer available.

Sergio

Nico said...
This comment has been removed by the author.
Nico said...

Hi Susan! I was wondering, would you happen to know if I can use sericite mica treated with carnauba wax in (matte) lipstick formulations? I read that it's an opacifier but lets pigments stay true to color, unlike with titanium dioxide which lightens colors significantly. I usually just see it used for powder products but I was curious about the carnauba wax treatment.

Sorry about deleting my first comment. Something went weird with it!