Q:
Hero's band unable to gem
A:
You can only upgrade it if the jewel doesn’t have a specific level threshold. The Hero’s Band is only Lv.1. I wanted to put a Gold Doubloon into my Hero’s Band, but that doubloon requires Lv.35+ items, so the Hero’s Band is a no-go. I believe the only things that can be put into the Hero’s Band are:
Amber, Garnet, Malachite, Pearl, Tiger’s Eye, Turquoise (Pebbles & Adorned Jewels), & Copper Doubloon.
I’m currently wearing mine with a Copper Doubloon, and I’ve had it equipped for the 51 days I’ve been playing (despite being a Lv.400 Jeweler, I prefer event items & cooler items over amazing stats).
I’ve NEVER been able to upgrade ANY trinket. Seeing as my weapons and armor have runes and sigils, the only upgrade slots I have left are on the trinkets. I keep tying to use the various interesting jewels, Medallions and the like I come across in the game on them but they end up getting sold instead. Kinda sad really. I’ve bought trinkets with jewels in the upgrade slot, but when I try to do it myself, it ALWAYS fails.