Warm Mythic Caves: Where Topaz Actually Spawns
Topaz in Mythic Upgrades is a Warm Mythic Caves resource, and that single fact explains why players who strip-mine ordinary caves for hours come up empty. The mod adds its own underground cave biomes, and each one carries a fixed pair of gems. Warm Mythic Caves hold 
Topaz and 
Citrine. Cold Mythic Caves hold 
Aquamarine and 
Peridot. Mine outside those biomes and the only topaz you will ever meet is the geode variety described further down.
Finding a Warm Mythic Cave
The mythic cave biomes are cave biomes, so they never appear on the surface. They replace the interior of normal cave systems the way lush caves and dripstone caves do, which means the fastest way to find one is to travel underground with a wide field of view: large open cave systems, ravines and abandoned mineshafts all cut through them.
Two cues tell you the moment you have arrived:
- Colour. The cave interior is built out of the gem's own stone, so a warm biome reads as a wash of orange-yellow topaz and citrine tones against grey rock.
- Sound. The mythic cave biomes play a soft ambient chime. If you hear it while spelunking, stop walking and look around; you are inside one or standing next to it.
What generates inside the biome
Once you are in a Warm Mythic Cave, topaz is not scarce at all. Four separate things are placed there, and they stack on top of each other:
Topaz Ore and 
Deepslate Topaz Ore are attempted ten times per chunk, spread evenly anywhere from Y -64 up to Y 32. The deepslate variant appears wherever deepslate has replaced stone, so below roughly Y 0 you will see the darker version almost exclusively.
Topaz Schist generates as large blobs, thirty attempts per chunk, from Y -64 to Y 30. This is the decorative stone of the biome and it is what gives the walls their colour.
Block of Topaz Crystal generates as smaller blobs, eight attempts per chunk over the same band.
Budding Topaz Crystal and its buds are placed fourteen times per chunk. These are the clusters growing off the walls and ceilings.
Ore is the densest single source, but crystal clusters are the faster one to farm, because each cluster hands over four shards instead of a single gem.
Topaz geodes outside the biome
There is a second, much quieter source that works anywhere. Topaz geodes generate in every Overworld biome, not just the mythic caves, at an average rate of once every twenty-four chunks. They sit low, between six blocks above the world's bottom and Y 30, which puts them squarely in deepslate territory.
That rarity is worth reading carefully. One geode per twenty-four chunks is roughly one per four hundred blocks of travel in a straight line, so you will not stumble across them casually while building a base. They are worth breaking into when you find one, but they are not a farming strategy. The same rule applies to the other three cave gems, so a geode you crack open underground could just as easily be citrine, aquamarine or peridot.
Mining it properly
The drops are worth knowing before you swing:
- Topaz Ore and Deepslate Topaz Ore each drop one Topaz. Fortune uses the ordinary ore-drop formula, so a Fortune III pickaxe roughly doubles your average yield. Silk Touch returns the ore block itself.
Topaz Crystal Cluster drops four 
Topaz Crystal Shard when broken with a pickaxe, and Fortune raises that further. Break it with anything other than a pickaxe and you only get two. Silk Touch returns the cluster intact, which is the option to use if you want to replant it as decoration.- Budding Topaz Crystal drops nothing at all, in any circumstance. It cannot be harvested, moved or duplicated, so leave it in place and treat it as a renewable farm: the buds regrow, the budding block does not.
Buds themselves come in small, medium and large forms, with the cluster as the final stage. Harvest only fully grown clusters and the same wall keeps producing.
Turning topaz into gear material
Raw Topaz is not the crafting ingredient; 
Topaz Ingot is, and it is deliberately expensive. Four Topaz plus four 
Necoium Ingot combine shapelessly into a single Topaz Ingot, which means every ingot costs you a trip for necoium as well. Nine ingots press into a 
Block of Topaz for storage, and the block breaks back down into nine.
Crystal shards run on a separate track. Four Topaz Crystal Shard make one Block of Topaz Crystal, which polishes into 
Polished Topaz Crystal Block four at a time and from there into bricks, pillars, slabs and stairs. Shards also make building stone directly: one 
Cobblestone plus one Topaz Crystal Shard yields Topaz Schist on 1.21.1, and the 1.20.1 version of that recipe takes two of each and returns two.
One version difference is worth flagging if you are following an older tutorial. On 1.20.1, 
Cut Topaz Crystal Pillar is made from four 
Topaz Crystal Pillar; on 1.21.1 it comes from two Polished Topaz Crystal Block instead. The end product is the same block, but the input changed.
A practical route
Head down to deepslate depth, follow open cave systems rather than digging tunnels, and listen for the chime. When you find a Warm Mythic Cave, clear the crystal clusters first with a Fortune pickaxe for shards, then work the ore veins on the way out. Leave every budding block untouched, and write down the coordinates: unlike a geode, that cave keeps producing for the rest of the world's life.