Physical Sunscreen can be defined exactly how it sounds - a physical layer or 'blocker' to the skin against UVA and UVB rays - think Bondi Rescue white zinc situation in it's more classical form.
Don’t worry - you wont be heading to the beach with stripes across your face. Although physical sunscreen formulations tend to be thicker and may leave a white-ish cast on the skin (it can look a little bit chalky under make up for daily use), the naturally broad spectrum formulation deflects heat and energy off and away from the skin so it's suitable for sufferer of eczema, rosacea and redness.
Added bonus - no waiting time is needed and it has a long shelf life. It starts protecting your skin as soon as its applied - it's that easy! However, it does rinse of easily in water or with those inevitable summer sweats, so make sure you apply thoroughly.