Formula: Mg(OH,F)2.2Mg2(SiO4)
Reflected/transmitted colour: pale yellow to colourless
Pleochroism: α colourless, very pale yellow, brownish yellow, β colourless, yellowish green, γ colourless, pale green
Optical isotropy/anisotropy: biaxial
Optical sign: +
Refractive indices: α = 1.592-1.617 (higher for titanochondrodite), β = 1.602-1.645, γ = 1.621-1.646
Birefringence δ: 0.028-0.034
2Vγ angle: 50-85°
Dispersion: r > v, strong
Optical orientation: α Λ z 22-31°, γ = y
Optical axial plane: ┴ (010)
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