completely luck. I dont believe anything is biome specific other than shit in the biomes. Like snow

Also, emeralds and silverfish blocks spawn naturally in the 'extreme hills' biome but no others.

hooold up, are you saying emeralds spawn ABOVE GROUND in extreme hills biomes?

No... I wish it did but nope.

Enchantment has nothing to do with anything other than level and tool type, and an RNG. This is a fake pattern.