Is mineral makeup great for sun protection? Short answer: no.
There’s a bit of misunderstanding out there regarding how well your mineral makeup will protect your skin from sun damage. This is partially due to the fact that mineral makeup contains both titanium dioxide and zinc oxide – and both provide your skin with a natural UVA/UVB barrier, and not-totally-true marketing efforts that exaggerate the benefits of mineral makeup for sun protection.
Given a high enough percentage of titanium dioxide and zinc oxide, there can be a good physical UVA/UVB barrier, however wearing mineral makeup is definitely not the same as wearing a good quality sunblock. You would have to wear a lot of your mineral makeup than you intend to wear, to give you adequate sunblock protection – mineral makeup typically offers sunblock protection for basic exposure to the sun, such as running a few errands.
So in a nutshell, leave the sunblock protection to the experts and you’ll be protecting your skin from harmful rays the right way. Your mineral makeup should be used for bringing out your already-healthy skin’s natural beauty.