Formula: MnBe(PO4)(OH,F)
Reflected/transmitted colour: Pink to colourless
Pleochroism: orangish (x), red (y), dark red (z)
Optical isotropy/anisotropy: Biaxial
Optical sign: -
Refractive indices: α = 1.638-1.640, β = 1.658-1.662, γ = 1.664-1.667
Bireflectance/Birefringence δ: 0.026-0.027
2V angle: 46-55° (calculated), 51-57° (measured)
Dispersion: Moderate, r > v
Optical orientation: Y = b, X Ù c = -31°
Optical axial plane:
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