Previous Post Quote: Nope the gem can and has been used by itself, the others act as stabilizers for it to ensure reality doesn't get torn asunder. Oh geez then Adam really shouldn't have trusted him with it. Quote: Thanos used it for a moment when he took it from the Collector, he used it again to briefly revive Mar-Vell.

At the time Adam Warlock went with the logic that Thanos is the only one besides Warlock himself that really understands the gems and that ironically Thanos would make an excellent choice to guard one of the deadliest of the six.