Reflected/Transmitted light color: colorless
Pleochroism: absent
Optical isotropy/anisotropy: biaxial
Optical sign: -
Refractive indices: α = 1.518-1.529, β = 1.522-1.533, γ = 1.524-1.539
Birefringence δ: 0.006-0.010
2V angle: 34 degrees
Dispersion: r > v
Extinction agnel: oblique 5-to 19 degrees with respect to (001)