I got the basic recipe for this powder from this site, which suggests using a mixture of cornstarch and French green clay. To color the powder they use cocoa powder.
I have tried using this recipe and a few different variations.
First, let me describe my skin, so that you have an idea of how to adapt it to work for your skin. I have total combination skin. My forehead and chin get oily, and my nose and the skin around it can get flaky from dryness on occasion.
The first time I tried this, I used a little clay (I used white clay instead though, as I had it on hand already), some cornstarch, and enough cocoa powder to get the mixture to match my skin tone. It looked good, but it hurt a little--much like when you leave an irritating mask on for too long. The skin on my forehead also felt tight. I knew it couldn't be the cornstarch, as cornstarch is an ingredient in many of the store-bought cosmetics I have used before. (You might have seen it listed on ingredients lists as "zea mays".) It didn't seem to me that the cocoa powder could be the problem, so I decided to experiment by eliminating the clay.
I used this cornstarch/cocoa powder combination for several weeks and loved the way my skin looked. I didn't break out any worse than I would have if I'd been using a store-bought powder. In fact, if I followed a regular face cleansing routine and made sure I washed my makeup off at night I had clearer skin than I did using store-bought powders. I'm really bad at getting my act together in the evenings and washing my makeup off though, so I'd still break out of course, but I don't think it's necessarily from the cocoa powder.
The one thing I did have a problem with in regards to the cocoa powder was that I have some enlarged pores on my cheeks, so it would sometimes settle into them and look pretty unattractive all day at work until I had a chance to go home and wash my face. I'm wondering if I would've had that problem still if I had used a finer cocoa powder, or if I had done a better job of mixing the two ingredients.
In the end though, I ended up eliminating the cocoa powder too. I have very light skin--especially in winter. I have been able to use cornstarch alone with pretty cool results. Since I have lighter skin, if I use a just light dusting it doesn't make me ghost-white but still mattifies (i.e. gets rid of oiliness) my skin. It hasn't caused any breakouts either; even on the days I don't wash my face before bed. My complexion looks way better than it did when I was using store-bought powders and I'm not putting possibly harmful ingredients on my skin anymore. Pretty awesome.
What will I do when summer comes and I have a little more color? I'm not really sure about this part yet. I'm not willing to pay over $20 for the all-natural face powders out there--not to use straight from the box anyway. I am considering, though, buying one of these powders in a shade similar to cocoa powder and then mixing it with cornstarch (like I did with the cocoa powder) to make my summer-skin shade. I will have to write an update when/if I try this.
So, to wrap this all up, here are the combinations I think might work for different skin types:
Normal/Combination: cornstarch + cocoa powder to color (eliminate if you have light skin)
Oily: cornstarch + clay (go for the French green though, not the white) + cocoa powder to color (eliminate if you have fair skin)
Remember, the cocoa powder shouldn't make you breakout or anything unless you're bad like me and don't wash off your makeup. (Cocoa powder actually has antioxidants in it and is used in mask recipes all the time because of this.) Just wash your face! I'm actually going to go do that right now...
PS -- Corn starch is rated as only 0-1 (on a 0-10 scale, with 10 being the worst) on the Environmental Working Group's Skin Deep Cosmetic Safety Database. French green clay, white clay (aka kaolinite), and cocoa powder all received zeroes.
(A version of this article was originally posted on my old blog, Glamoursaurus Goes Natural, which is now defunct.)