Phenanthroline is a tri-nuclear aromatic nitrogen heterocycle that is commonly used to form a complex with ferrous ions. This complex is termed "Ferroin", and is used as an indicator in oxidation-reduction systems like the titration of ferrous salts. Phenanthroline is also used in the determination of nickel, ruthenium, silver, and other heavy metals. When recrystallized from the melt, will slowly crystallize, forming beautiful dendritic needle-like crystals. The time-lapse movie was made using a modified version of the Intel Play QX3 microscope equipped for polarized light illumination with a full-wave (first order) retardation plate.