Why Emeralds are rarer than Diamonds

Diamonds and Ancient Debris are the best thing to get  but emeralds are rarer than diamonds and Ancient debris

Not really emeralds are not rare because you can trade with villagers

*Ores

Emerald ore (at least prior to 1.15) was the rarest ore bc it could only be found in the extreme hills biome. I'm not sure if ancient debris is rarer.

if you find the ore it must be under a mountain biome

The rarest ore for the 1.18 ore generation which was put into 1.17 by accident is the deepslate emerald ore cuz it has to spawn below Y level 16 and under a mountain biome

Its not rarer if u mine in a extreme hills biom 

btw its only that rare cause it only spawns in the extreme hills biom

it's mountains

the rarest version is deepslate emerald ore you need silk touch + Y level below 16 + under mountain biome

i have found a bit of emerald ore from mountains

(no variation)

also I think the 1.18 the mountain boime might have emerald more common but it is like in the sky right now in 1.17

i think its very commen in mountains too

sry for extreme hills tried too translate from german lol

ems are the most common thing in vault hunters bc in vaults you can find them in DROVES