Hawaiian volcano has mesmerising blue lava

This mesmerising blue lava from a Hawaiian volcano is actually an optical illusion.

A video captured blue lava tumbling out of the Kilauea volcano in Hawaii on Wednesday.

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The effect, sometimes referred to as the 'blue hour,' occurs as the sun sets, causing light to refract off the glowing lava and creating the optical illusion of blue lava.

Kilauea is one of the most active volcanoes on the Big Island of Hawaii.

French photographer Olivier Grunewald revealed to Smithsonian Magazine that the lava is not blue, but rather contains blue flames caused by burning sulphur.