Bf has a Valentine’s Day gift for me and I can’t figure out this hint

(for all you religious people out there) apparently it appears when Mary appears, but it is made of something that starts with an A and ends in a U, also the second letter is o.... also the number 24,000 is involved ???

& a while ago when he was thinking of a hint i saw he was looking at a periodic table .... AU is for gold and the second letter in gold is an o so .... i don’t know !! help ??