Ruby is one of multiple gemstones you can find while exploring in Hytale, and these stones are very useful for crafting various arcane gear such as staffs and totems, so you don't want to neglect them ...

The Ruby and Wraithstone items in Doom: The Dark Ages are used to upgrade the player’s arms and armor. The player needs to work hard to find them all, as they’re often hidden by enemies or puzzles.