Zinc Stearate is the "magic bullet" which helps improve adhesion for powder cosmetics.
Particle size (<74 microns).
The product is derived from palm oil.
Try this as a starting experiment:
- Take 1.8 grams of your favorite premade cosmetic.
- Add 0.2 grams of zinc stearate (this is 10%).
- Put it in a 3x4 zip lock bag.
- Zip and rub together between your hands.
- Squeeze in 6 drops of jojoba oil, zip shut and rub some more.
- Run through sieve and press into the small round 26 mm pan in three layers.
Videos, photos and more specifics to follow, but this will get you started.