Blue-glass pāhoehoe

First recognized in Kalapana in 1990, these pāhoehoe flows appear bluish with dense, glassy crusts. These lavas are generally observed later in the life of an inflated pāhoehoe flow. The degassed nature of the lava promotes the formation of solid glass, rather than bubbly, crusts. The bluish color may be the result of the natural iron and magnesium in the lava.