The Birch Moisture Sun Cream by ROUNDLAB is a chemical sunscreen. Chemical sunscreens contain ingredients that absorb UV rays and convert them into heat, providing protection. This is different from mineral sunscreens, which use physical blockers like zinc oxide or titanium dioxide to reflect UV rays. Chemical sunscreens are often preferred for their lightweight and non-greasy feel, but they can sometimes cause irritation for those with sensitive skin. It's important to patch test new sunscreens to ensure they suit your skin type.