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)