XPL Polariser + analyser with conoscopic illumination


We can observe phenomena linked to birefringence and the position of the optic indicatrix which are related to the form of the crystals.

By working without the condenser incorporated (orthoscopic illumination) you can study the interference colour, the extinction angle, the sign of elongation, twinning and mineral alteration.

When the condenser is in place (conoscopic illumination), principally, you can observe the interference figure and the optic sign of the crystals.

Once the properties to be observed with orthoscopic illumination have been analysed, we shall go on to work with conoscopic illumination.

The following accessories are included:

Polariser + Condenser + Analyser + Bertrand Lens

The property which is to be observed here is the Interference Figure, from which the Optic Sign (and Dispersion) can be deduced.

Consequences of conoscopic illumination

How is the interf. fig. seen?

The function of the interf. fig.

The uniaxial versus biaxial interference figures

Uniaxial interference figures

Biaxial interference figures

Interf. colours and interf. figures

Optic sign



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