2.2.8. OM and PLM

The samples' structure was studied in reflected VIS and UV light on a Leica DMRX polarised microscope at magnifications of ×50, ×100, ×200, and ×400 coupled with a Leica DFC295 digital camera. PLM was carried out in transmitted VIS light at magnifications of ×100, ×200, and ×400 using the methodology developed by Peter and Ann Mactaggart [19].

#### 2.2.9. Preparation of Samples

The samples selected for the cross-sections were embedded in a fast-curing acrylic resin, ClaroCit from Struers (Cleveland, OH, USA), and fine polished. The PLM pigment dispersions were prepared with a Meltmount nD = 1.662 mounting medium from Cargille (Cedar Grove, NJ, USA).
