Formula: (Na,Ca,REE)5(Fe,Mn)(Zr,Ti)(Si3O9)2(OH,Cl)
Reflected/transmitted colour: colourless
Pleochroism: in thicker sections w colourless, pale yellow, yellowish pink, ε colourless, pale yoeelow, pink
Optical isotropy/anisotropy: uniaxial
Optical sign: +, -
Refractive indices: w = 1.588-1.658, ε = 1.594-1.636
Birefringence δ: 0.000-0.022
2V angle:
Dispersion:
Optical orientation:
Optical axial plane:
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