Optical Properties of Neptunite are its behavioral responses towards light. While few optical properties can be identified with naked eyes, other require special instruments by the gemologists to identify them. Neptunite optical properties like luster, clarity, refractive index etc. are used to determine the non-destructive methods during gemstone identification and evaluation.
Neptunite luster is the quantity of light the crystal reflects when light is incident on it. Neptunite which is commonly found in Black, Red, Brown color, is Translucent in nature. It possess Vitreous luster.