....hidden in moon's mantle

Interesting, but not so "exotic".

On Earth, we have a mix of S_32 (95%), S_33 (1%) and S_34 (4%) approximately. https://en.wikipedia.org/wiki/Isotopes_of_sulfur

In the Moon, there is less S_33. So it's a different mix, but not a mix that includes a lot of unusual things, just more of the usual things.