- (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.
[T.D. TTB-140, 81 FR 59462, Aug. 30, 2016]