The short answer is: yes.
The semi-short answer is: yes, but you may not be satisfied with the results.
And the longer answer follows.
The color additives we sell are (for the most part) considered a "raw ingredient" for use in making cosmetics. Having said that, they are all safe to be used directly on the body at 100% concentration.
The reason that people alter the colors is to make them perform better.
For example, in a loose powder cosmetic, a colored mica by iteself will tend to rub off rather quickly. For this reason, at a minimum, you should put on a primer first to make sure the color stays in place. Alternatively, you can start adding things to the powder to make it have more adhesion. Our TKB Matte Texture Base is one option, and there are others.