One volcano on Earth erupts lava too cool to glow

Tanzania's Ol Doinyo Lengai is the only volcano known to erupt natrocarbonatite, a sodium-carbonate lava so much cooler than ordinary magma — around 500-600°C — that it doesn't glow red at night, and so thin it can outrun a person on foot. Exposed to humid air, the black lava rapidly weathers to white, giving the 'Mountain of God' its permanently snow-capped look despite sitting almost on the equator.

— Wikipedia contributors, Ol Doinyo Lengai — Volcanoes of Tanzania