In uniaxial coloured stone, dichroism is possible, in bi axial stone, trichroism is possible, if absorbtion is identical no pleochroism
Trichroism in a tanzanite
Dichroism in a cordierite
how to use a dichroscope
Doubling in Mossanite and Zircon
Chelsea
Polariscope

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Dichroscope
Dichroscope Doubling
Magnetism
 UV

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Pleochroism or selective absorbtion

Dichroism in a cordierite

Trichroism in a tanzanite

Dichroscope principle

Doubling

Conoscope
Refractometer

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Lab tools
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