Idea of the use of rubies in the comments.

Minecraft: Emeralds and rubies. 1.3 update

You could put them on tools or armor, and this will give you some boosts, basing on which (special) enchant will be on the ruby.

Examples: Strength Boost, Speed Boost, Range Boost, Jump Boost, Protection Boost, Knockback Boost. And maybe more. Yeah, I know enchants exist, but wait.

On the Smithing Table, you could put the ruby off the tool/armor, but them the enchant will dissapear. What is it for? Because the ruby will break with the armor. So if you will take the ruby off the almost broken armor, you will save a ruby and you could enchant it again.

And here is the not important thing,
Where will be the rubies.

Tools/Weapons:
Sword: on the horizontal thing below the blade
Pickaxe: in the middle of the part for mining
Axe: in the middle of the blade
Shovel: also in da middle
Hoe: at the start of the blade
Bow: in the middle of the handle
Crossbow: maybe in the middle of the whole weapon.

Armor:
Helmet: in the middle of the forehead
Chestplate: in the middle of the chest
Pants: in the... On the knees? (It will somehow double just for texture)
Boots: in the middle of the boots (the rubies will also double)
Shield: this time, it will be X6. Rubies will replace the gray dots.

And the rubies would be a new ore, they would not replace emeralds.

Good idea. But example only one copper weapon
Maybe axe

you could enchant the copper sword with channeling

WAIT

ADD COPPER-TIPPED ARROWS, ENCHANT ARROWS WITH CHANNELING

I remember rubies. It was weird ad. They weren't used for anything that I could remember.

rubies were the original emerald i think

Yes, and they freaked me out. I got them confused with Redstone