Hematite can activate, balance and earth ground and root chakra. It is great for haematogenesis and blood circulation because it contains a lot of iron. Balances the blood pressure, also male and female energies. Gives strength and courage.
Flat stone suits the best for healingwork, because it covers the chakra and the contact surface are is the largest. Also it will not fall off the body and is large enough to draw forth energetic and physical changes. Flat stones are also the best to carry in your pocket.