[1] One main type of PSC is composed of mostly supercooled droplets of water and nitric acid and is implicated in the formation of ozone holes.

This type of PSC is also called nacreous (/ˈneɪkriəs/; from nacre, or mother of pearl), due to its iridescence.

In the extreme cold of the polar winter, however, stratospheric clouds of different types may form, which are classified according to their physical state (super-cooled liquid or ice) and chemical composition.

[3] Due to their high altitude and the curvature of the surface of the Earth, these clouds will receive sunlight from below the horizon and reflect it to the ground, shining brightly well before dawn or after dusk.

In the Northern hemisphere, the generation of lee waves by mountains may locally cool the lower stratosphere and lead to the formation of lenticular (lens-shaped) PSCs.