@Ronja Try adding Crystal Shaders to your project. That might fix it. Otherwise, just select from an existing material using the instructions @medievalmermaid gave. Look for metal or glitter or something like that.
@bennyworm No problem, deadass was searching for her for awhile when i first started playing cuz the creator lowkey sucks cause she couldnt be bothered to change the mats for quest (legit takes maybe 3 clicks to do lol)