Reflected/Transmitted light color: colorless, pale brwon, pale purplish brown, pale greenish brown or pale green

Pleochroism: Pleochroic in various shades of green and brown. In Plane Polorized Light (PPL) a thin section of Hornblende ranges from yellow -green to dark brown. Green varieties usually have X= light yellow green, Y=green or grey-green and Z=dark green. Brownish varieties have X=greenish-yelow/brown, Y=yellowish to reddish brown and Z=grey to dark brown

Optical isotropy/anisotropy: biaxial

Optical sign: -

Refractive indices: α = 1. 614-1.675, β = 1.618-1.691, γ 1.633-1.701

Birefringence δ: 0.019-0.026

2V angle: 52-85°