“Caffeine crystals
ANNIE CAVANAGH AND DAVID MCCARTHYThis false-coloured scanning electron micrograph shows caffeine crystals. Caffeine is a bitter, crystalline xanthine alkaloid that acts as a stimulant drug. In plants, caffeine functions as a defence mechanism. Found in varying quantities in the seeds, leaves and fruit of some plants, caffeine acts as a natural pesticide that paralyses and kills certain insects feeding on the plant. The main crystals of caffeine were 400-500 microns long; however, this crystal group formed on the end of the larger crystal and measures around 40 microns in length.”
