Conoscopic arrangement of the Petrological Microscope

Observing interference figures of minerals is done under the Conoscopic view of the petrological microscope. The conoscopic arrangement is set up as follows,

1.  The medium or low power objective is selected and selected grain is brought to the centre of the cross-hairs.

2.  The light intensity is increased by using the concave mirror or the intensity controller of the electric bulb.

3.  The objective is now changed to high power and brought very close to the the thin section (almost touching it).

4.  The analyzer is put to the "IN" position.

5.  The Bertrand Lens is also put to the "IN" position. (This will make the viewing scope small)