The rubi ore has the goal to make more usefuls moutains by adding a new precious ore : the rubi ! It only appears beyond y:100 and 4 rubi veins in 1 chunk. You have to grab an iron pickaxe before getting it ! Once you get it , place it a furnace to get rubi : you can make new items and blocks like the rubi glass just a like a cave block , useful to find easily hidden bases/caves (to craft it you will need 1 rubi and 8 block of glasses). You can also craft the rubi stick which gives you more hp for an amount of time but only 5 of durability and the stick has a cooldown (to craft it you will need 2 sticks and 1 rubi). There is the last tool : the rubi hammer which is very useful to optimize your inventory since it loots NOTHING and mines in 3x3 but only works with stone , deepslate , netherrack , end stone (it's useful to gain time and with a pickaxe and some skills you will understand how useful thim item is when mining in the overwold or in the nether to get netherite ores (to craft it you will need a block of rubi (9 rubis) and 2 sticks). That's also why i added the netherite hammer just like the rubi hammer but instead mines in 4x4 (to get it , it's just like any other netherite stuff : the rubi hammer + netherite ingot + upgrade item)
