Formalwear for a male priest of Lutina, goddess of protection.
Male priests are responsible for the domestic duties of the temple: cleaning, cooking, helping the priestesses bathe and dress. As such, they usually wear simple chitons for comfort and practicality. But for special events and ceremonies, they break out the FANCY robes. The clothing is made of moth-cocoon silk (a staple to Lutinite society, especially the clergy). Male priests rarely wear jewelry, but when they do, it's usually elaborate filigree pieces of plain gold, sometimes with colorless gems for sparkle.
Purple gems are reserved for priestesses, clerics, and paladins (always female). Their jewelry is simpler in design: stud earrings, thick chains with a gem pendant, brooches and buckles with stamped designs. Sturdy jewelry that can be worn into battle if needed. They wear moth silk as well, for casual clothes inside the temple and as underclothes and capes outside, but female clergy are more often seen in armor (leather or scalemail) than in plain clothes.
"But OP," you say, "if this is male formalwear, why is there so much jewelry? And why are there purple gems? The art contradicts the text." Well you see, THIS specific outfit is for Lutina's Chosen, who happens to be male. The abundance of jewelry and the presence of purple gems indicate his exceptional status.