LAPIS LAZULI

Underground, lapis lazuli comes out of deepslate lapis ore and lapis ore, ore that clusters in patches the way most valuables do, meaning some trips down come back empty. A Cleric at apprentice skips that entirely: 1 emerald buys 1, on demand, whenever his slot is open.

It also has somewhere to go once bought: it feeds enchanting at the table, brewing at the Cleric's own stand, and crafts into [object Object],[object Object]. Buying it back from the same profession that wants it for brewing is a short, closed loop.

Nothing crafts lapis lazuli from scratch. Mining it, unpacking a stored block of it, or buying it from a Cleric are the only three ways it ever ends up in an inventory.

One profession sells it. Visit a Cleric once he reaches apprentice, and 1 emerald buys 1, a fixed price rather than a rolled one, so a second cleric at the same tier quotes exactly the same.

Lapis Lazuli sells for as little as 1 emerald, from the Cleric at the Apprentice tier, and nothing else on the list costs less. The price is fixed rather than rolled, so a second Cleric will quote you exactly the same.

The Cleric at its apprentice tier asks 1 emerald for lapis lazuli. 8 of the 72 villagers that pay emeralds, emptied out:

a dark oak boat against 32 sticks for the same 1 emerald, 32 times the carrying, and the shortest wait is the Leatherworker at 37.5 real seconds of shelf, gathering not counted.

A brewing stand next to an unemployed villager makes him a Cleric, but lapis lazuli is not part of his opening tier. It appears at apprentice, one step up, which he reaches once he has traded enough experience out of his starting offers.

From there the slot sells 12 loads before it locks, and restocking brings the same fixed price back rather than a fresh roll, lapis lazuli included every time.

12 sales close the slot, and the brewing stand needs 2 real minutes to refill it. A Minecraft day runs 20 real minutes, room enough for two of those refills to land while you wait.

A full day at one cleric hands over 24 lapis lazuli, more than most enchanting and brewing sessions burn through before the next restock catches up anyway.

Skip the mine trip when the Cleric is closer. Deepslate and regular lapis ore both cluster in patches, so a dig can come back thin; a Cleric at apprentice gives a flat, known amount for a flat, known price every single time.

Fund it from the same brewing stand: the Cleric pays an emerald per 3 gold ingots, which is worth checking before spending emeralds earned elsewhere.

Also on the Cleric's list: rabbit foot, glowstone, scute, glass bottle, ender pearl, and nether wart, the rest of what one brewing stand can put on offer.

Every enchantment costs lapis as well as levels, up to three per go, and nothing else substitutes for it. A table without lapis in the slot offers you nothing, which makes this the one ore that gates a whole system rather than making an item.

It is also blue dye, one for one, and the only reliable one before you go looking for cornflowers. Nine of them pack into a lapis block and come back out again, so a block is storage rather than a one-way craft.

The ore generates deep and in generous veins, and Fortune multiplies what each block gives, so a single good vein tends to cover a world's worth of enchanting.