Because the Cross-and-Crown symbol has been used in more than one "application," the identification of RelicDude's pin is a matter-of-opinion. Here is my reasoning that it is more likely to be a Religious pin than a Masonic pin.
As shown at the York Rite / Knights Templar pins webpage, the York Rite version does not show the Cross-and-Crown emblem "by itself" (as it is on RelicDude's pin) ...but is instead shown with the motto "In Hoc Signe Vinces" around it on Maltese Cross "arms." I could not find any York Rite / Knights Templar pins showing
only the Cross-and-Crown on a disc.
Because RelicDude's pin's depiction of the symbol is so "plain-&-simple," I think it is more likely to be a Religious pin than a Masonic pin.
As I said in my previous post, the Cross-and-Crown emblem is fundamentally a Christian religious symbol ...and it has been used in many Christian Church applications (quite apart from its appearance on school-buttons and York Rite pins). For example, I saw people wearing Cross-and-Crown pins in my (Methodist) church when I was a teenager. Please real all the info here, at Wikipedia:
Cross and Crown - Wikipedia, the free encyclopedia
Here are some examples, which include the logo of the Free Bible Students organization, and on a Christian book-cover, and (formerly) its use on EVERY cover of the Christian "Watchtower" magazine, and on a Christian school-button.