Hessonite is a type of garnet stone that differs in chemical composition from other garnets. It is found in cinnamon, brown red, and brown/red colors. Hessonite is specifically used for astrological purposes related to Rahu, while garnet can be used for the planet Sun or any planet that matches the color of the garnet stone. One should not wear hessonite and other garnets together or mix it with yellow or red stones, as it can interfere with the stones' energies.