Cryogenic liquid hydrogen tanks are common in industry. These tanks have an inner vessel and an outer vessel. Between the two, the space is sometimes filled with perlite and a vacuum pulled to reduce heat transfer to a minimum to prevent boiling of the liquid hydrogen. This is the same volcanic rock used in other applications but it is dried in an oven as described here: Reference: http://archives.njit.edu/vol01/etd/1950s/1957/njit-etd1957-003/njit-etd1957-003.pdf Table 1 in this reference is on page 5 and shows typical chemical composition. Is it possible that this material in the state described (used as vacuum insulation) could adsorb hydrogen gas? Even a small amount of hydrogen?