The biggest mission in survival Minecraft is acquiring as many ores as possible. It's practically impossible to get through the game without doing at least a bit of mining, and so conquering those caves and ravines has always been an integral part of the game. While ores might seem as though they spawn randomly, there's a very specific way all of them are generated.
Some ores are so incredibly rare that knowing exactly their elevation and possible biome is absolutely key. Not all ores are found in the Overworld, however, and some resources can only be accessed once you've built yourself a Nether portal and accessed it. Here's where to start when hunting down specific ores in Minecraft.
Coal
Coal is the most common ore in the entire game and generally shouldn't be difficult for you to find. It's particularly in abundance at surface level in mountain biomes, but any cave will most definitely have it in its earliest and highest tunnels. The ideal elevation for it is between Y:5 and Y:52.
Coal is an essential resource, mainly used for fuel and for making torches. It can also be used to make campfires, and as such, is a necessity that players should focus on getting right off the bat when spawning into a new world.
Iron
Iron is the next most common after coal, and it's a resource that is continuously needed to make mid-tier iron gear. Unlike coal, iron has to be smelted once it's mined, so by definition it requires some type of fuel to take full advantage of. Iron is found in all types of caves, between Y: 5 and Y: 52.
Iron has an interesting role in the game. Even after acquiring quite a bit of diamonds, it remains a resource players will need to continuously mine in case they'd like to build necessities like redstone farms and other advanced machinery.
Nether Quartz
Nether Quartz is a special resource that can only be found in the Nether. Since the 1.16 update, some biomes like the Nether Wastes are generally better for finding it, since the landscape is so barren and open. Overall, however, quartz spawns between Y: 10 and Y: 117 in abundance in the Nether.
Quartz is used in a few select redstone crafting recipes. More importantly, it's a nice decoration block, and mining it yields quite a bit of experience points. Otherwise, it has no use than its cool appearance.
Gold
Gold has become even more important thanks to the 1.16 update. It's used in some redstone recipes and is a trading item with Piglins. Gold can be found in the Overworld in caves usually between Y: 5 and Y: 29, but in the badlands biome it generates more commonly and higher up. Like iron, it has to be smelted into ingots in a furnace.
Gold is also found in the Nether, where it drops directly as gold nuggets. Just like quartz, it generates between Y: 10 and Y: 117 in just about any biome, but it's easiest to find in Nether Wastes due to the openness of the biome.
Redstone
If you're looking to make any redstone builds or machinery, it's absolutely necessary to find some redstone first. It's quite a common ore once you dig down to the right elevation, which is between Y: 5 and Y: 12. The ore drops directly as a dust, and will be more abundant if mined with a Fortune pickaxe.
Redstone's only function is in redstone-related crafting recipes. Otherwise, it can be pretty much ignored completely, although a few common recipes like the compass will still call for it. Redstone, like quartz, is a decent way to get some experience points when mining.
Lapis Lazuli
Lapis Lazuli is a dark blue ore with a distinct pattern slightly different from other ores. It spawns mostly underground and in caves in the Overworld, between Y: 13 and Y: 17. Lapis drops directly in its usable form, so it requires no smelting or crafting.
The primary use for Lapis is enchanting. In order to get any enchantment, the player needs to place between one to three pieces of Lapis into the enchanting table interface. Level 1 enchantments requires one piece, Level 2 needs 2 and Level 3 requires 3. It can also be used as blue dye.
Diamond
Diamonds are perhaps the most highly coveted material in the entire game. They're quite rare in the Overworld, though they aren't the rarest resource out there. This light blue ore will drop directly as diamonds and is usable immediately.
Diamonds allow the player to craft the strongest type of gear available until the Netherite upgrade. In order to even get Netherite gear, you need to already have diamond items which can then be upgraded using the blacksmith's table. Diamonds are best found by digging down to Y: 11, and then digging a long hallway with strips every two blocks apart.
Emerald
In the Overworld, the rarest ore is undoubtedly the emerald. Unfortunately emeralds aren't as popular as diamonds, because they can't actually be crafted into anything else than emerald blocks. Their main purpose is to serve as currency when trading with villagers.
Emeralds are extra rare because they only spawn underground in mountain biomes, so no other biome will have them. They can be found between Y: 5 and Y: 29, and it's recommended to mine them with a Fortune pickaxe, since they usually spawn in single blocks.
Ancient Debris
Introduced in the 1.16 update, this resource is exclusive to the Nether. It's a special block that doesn't take explosion damage and can even float in lava. Ancient debris is mostly found at Y: 15, and the effective way to mine it is to mine a long hallway and every five blocks or so at head level mine out a tunnel and place a bed at its end to create an explosion.
Once the debris is smelted it will yield one Netherite scrap. Four a required to make one Netherite ingot (along with four gold ingots), and one ingot is enough to upgrade one piece of diamond gear, enchanted or not.