Talk:Argon Crystal/@comment-94.74.234.14-20160718174748/@comment-25254386-20160728190306

Yes, but 40Ar is really only abundant on Earth, on the otherhand 36Ar is the most common isotope of Argon in the universe. So it is likely Argon Crystal is not made up of one of Argon's stable isotopes, rather it is composed of 36Ar isotopes that are unstable, hence its decay over time.