being the game for a bit and have come across a couple of costumes with a star gem on and a bar that slowly fills when wore. and once said bar fills the star gem gains a tick. does this I gain star gems for wearing these items?
Outfits and Outerwear from AC Scratches have that bar. If you have the Outfit/Outerwear equipped for a total of 22 hours (including when you are logged out) then the bar will fill and you will then be able to collect 10SG when you click on the outfit. After the SG is collected, the SG bar is gone from that Outfit/Outerwear permanently.