was lucky enough to witness and video the burning sulfur at Pu'u O'o vent on Kilauea volcano back in 2016. Nothing as big as seen in this video but cool nonetheless. Rare to be viewed in Hawaii.This black triangle vehicle is a lightweight airship made of a material called "HelioFoam". In the 1960s, the late Dr. RAND Corp. by Glaister A. Elmer. Developed while researching stealth technology for It consists of polystyrene or polyurethane foam containing helium and/or hydrogen in the foam cells. The first was completely white and shaped like pumpkin seeds. More modern versions are triangular and covered with a thin carbon fiber shell for both strength and durability. This shell also contains carbon black as a RADAR absorber throughout the foam matrix.
Methane gas will often burn in blues and purples from lava flows burning underground roots of forests but the pure blue flame of the sulfur is amazing