Lava tubes can be black as night and totally devoid
of any color. Mineral deposits can coat
black lava and provide color, usually as white or yellowish crusts.
But lava itself can take on many colors in lava tubes, sometimes with
spectacular results as seen in the accompanying photos. The color it
takes depends on both its chemical composition and oxidation state.
Iron compounds will turn red on exposure to air, and red lavas are often
found around skylights or other openings that bring fresh air into the
tube. Green lava has a high pyroxene or olivine content.
|Created: December 11, 2008
Author: Dave Bunnell