if an item has 4 empty sockets you can put specific mythstones into it to craft a mythic affix which will turn it purple here’s a link to a post with the list Griffin’s Smithery: Mythics
if an item has 4 empty sockets you can put specific mythstones into it to craft a mythic affix which will turn it purple here’s a link to a post with the list Griffin’s Smithery: Mythics