Section 21.105-T1 - Cornmint oil (Mentha arvensis and Mentha canadensis(a)Specific gravity at 25 °C. 0.895 to 0.905.(b)Refractive index at 20 °C. 1.4580 to 1.4590.(c)Optical rotation at 20 °C. -18° to -36°.(d)Alcohol content (as menthol). 65 percent minimum.(e)Ketone content (as menthone). 5 percent minimum.