©Lin Yangchen

When I saw polarized light at home for the first time, it felt like North Korea attaining nuclear launch capability. As the polars crossed and the view through the eyepieces turned inky black, criss-crossed by the glowing Newtonian interference colours of birefringent cellulose microfibrils and mysterious green-and-orange spherulites, I had a Messiaenic moment.

The French composer and organist Olivier Messiaen was famous for associating musical sounds with colours down to specific combinations and patterns of subtle shades. In fact, he often invoked minerals in his descriptions, such as amethyst, sapphire and lapis lazuli. Reconstructions of his visualizations look uncannily like petrographic thin sections under a polarizing microscope. The colours manifest themselves in crystalline clarity in the organ's tonal timelessness, the author's favourite being the monumental 18-movement Livre du Saint Sacrement.

Longitudinal section of onion root prepared by the author in high school in the 1990s, sprinkled with spherulites of unknown origin through crossed polarizers with a λ waveplate and matching two of Messiaen's descriptions. The shades of background pink "range from brownish red to very pale pink, passing through bright pink and orange-pink, forming vertical serpentine designs. The whole evokes two very well-known pink stones—rhodonite and rhodochrosite." (translated from French)

The Fast Circular Transform, a new method for appreciating petrographic thin sections in cross-polarized light by rotating the stage during a long exposure after centering the objectives on my petrographic microscope. The grey tones are from plagioclase and the colours are from pyroxenes in a sample of Singapore Gombak Norite. For video, see my Rock Disco YouTube playlist.

Emergency polarizing filter holder for getting cross-polarized reflected light before the delivery of my 3D-printed custom holders. Cardboard is a good material as you don't have to cut it too precisely and can simply jam the filter in the hole without glue.

The esoteric orientation plate
Ultra-nerdy retardation compensators
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