Q: Just wondering why carrier oil is added to a dry loose blush or eye shadow formulation. Do you need it if you aren't pressing the product?
A: The oil added provides moisture in an otherwise drying product. So it's not necessary, but it's helpful. I suggest jojoba oil because it does not degrade.
Q: Also, does the zinc oxide make it have good slip and adhere to the skin or can it be replaced with something like a vegetable powder?
A: Zinc is good for the skin and also adds opacity and adherence. A vegetable powder may degrade and may not have the same properties, but go ahead and try it!