It's essential to understand the difference between chemical sunscreens and non-chemical sunblocks.

The non-chemical blocks use either zinc or magnesium dioxide to physically prevent the sun from reaching your skin. That's where the white stuff comes in.

There is some controversy as to whether chemical sunscreens are bad for you or contain cancer-causing ingredients.

I myself use Neutrogena non-chemical sunblock for Sensitive Skin. It looks a bit whitish at first but that mostly disappears after a few minutes. Smoothes on nicely.