Well preserved after 1959 eruption of Kīlauea Iki Pele's hair
Pele's hair/ˈpeɪleɪzˈhɛər/ is stone mineral threads or fibers formed when small particles of molten material are thrown into the air and spun out by the wind into long hair-like strands. The diameter of the strands is less than 0.5 millimetres (0.020 in), and they can be as long as 2 metres (6.6 ft). The material is gold or golden-brown, and is commonly found downwind from active vents.
A manufactured version of Pele's hair made from basalt rock and recycled slag from steel manufacturing called mineral wool or stone wool is commonly used as a non-combustible, durable, dimensionally stable, UV stable, hydrophobic, vapor permeable building insulation for residential, commercial, and high rise building.
A hydrophilic version is used as a low water usage, high yield, soil substitute for hydroponic agriculture.