It's no big surprise that in a game called Minecraft, mining for valuable resources would be a central aspect of progressing to new stages of development throughout the game. Every ore has its use in making your life just that little bit easier when trying to procure food, weapons, and armor to survive the hostile world.
But ores and their materials can have completely different levels of usefulness when compared to one another; some ores completely change the flow of the game when found, while others might get occasional use but inevitably sit in storage waiting for their niche use case.
10 Copper
Copper Ore, as it is, just does not have enough uses to ever justify actively searching it out. For some nonsensical reason, it can't be formed into any traditional tools or armor, meaning in the early game, it won't have any use despite its abundance.
Even further, the few uses it does have are too specific and narrow to ever be needed more than once or twice. As it stands in the 1.19 update, Copper Ingots can be made into two non-cosmetic items– the Spyglass and the Lightning Rod. The Spyglass is an item that probably won't get much use in the first place, and the Lightning Rod is only ever realistically useful for spawning Zombified Piglins and Witches.
9 Emerald
Emerald Ore just barely squeezes its way above copper, and the reason is that it's useful for trading with villagers. It can't make tools or armor, which means that its sole purpose is as a currency. The trouble is that it’s easier to get emeralds from trading!
The main reasons that it falls so far down the list are that Emerald Ore is both difficult to find and only necessary for a few Villager trades. As of 1.19, the items you would be most interested in obtaining from trades are uncraftable Enchanted Books, such as the Mending book. Once you get those books, which, depending on the deal, could cost less than 100 emeralds, there are few things you can trade for that you couldn't more easily get yourself.
8 Quartz
Quartz Ore is the first ore on this list to be useful enough to warrant being hunted down during a playthrough. Quartz is found in the Nether and is relatively abundant, meaning that you'll never be short of it (unless you're planning on building a Quartz mansion with Quartz floors and little Quartz fountains to prance through).
Quartz is primarily useful for certain Redstone components with niche uses. The Daylight Sensor, for example, is a great way to make machines that work based on the time of day; the Observer can send a Redstone signal every time a block updates or breaks; and the Redstone Comparator serves a number of complex functions that can't be done with basic Redstone components.
7 Coal
Coal will always be useful in Minecraft since a decent number of the ores on this list need to be smelted to be useable. Coal and its block form are some of the most efficient fuel sources in the game, and given how easy they are to find and make, it's likely to be the fuel source you use the most. Coal is also a critical component of Torches, which are useful no matter what level of development you're in.
The main reason this ore is not higher on the list is that most of its functions can be replicated by Charcoal, produced by smelting Logs in a furnace. Charcoal can't be turned into blocks, though. So if you want to smelt a high volume of items, you'll need a greater amount of fuel.
6 Gold
Many veterans of the older updates of Minecraft may be surprised that Gold Ore is not at the bottom of this list, but thanks to the 1.16 Nether Update, Gold is more useful than it once was. The most important use for Gold is in producing Netherite in combination with Netherite Scraps since Netherite is the highest tier of tools and armor as of the 1.19 update.
Gold is useful all across gameplay now, though still not exactly ever-present. At least one piece of Gold armor is necessary to make Piglins neutral to you, which for a player entering the Nether for the first time, can be a matter of life or death. Gold is also important in Piglin trading, which is one of the easier routes to getting enough Ender Pearls to reach the End.
5 Lapis Lazuli
Lapis does not have many uses, but its primary use is integral to reaching the highest levels of development in your playthrough. Lapis has uses as a dye, sure, but the use that you should be interested in is its role in Enchanting.
To use an Enchanting Table, you need one to three pieces of Lapis to access the three possible levels of Enchantments. These Enchantments can be useful in making your armor more powerful, your tools more efficient, and both longer lasting. The sheer number of Enchantments you can apply and use make this ore worth searching for in as many stacks as you can get your hands on.
4 Ancient Debris (Netherite)
Ancient Debris isn't necessary to find, but it's in the endgame for most players since once you get your hands on Netherite, you're likely to never need to replace your tools or armor again. Netherite items don't burn in the lava and have ridiculous durability that justifies just how rare Ancient Debris really is.
Netherite can also be used to make a Loadstone, which will allow compasses to work in the Nether and the End, as well as forcing a compass point to a specific point in the Overworld, which can make exploring all dimensions much less confusing. The main reason it doesn't take the number one spot is that while its uses are fantastic, they are also few.
3 Diamond
Diamonds! Diamonds make the second-strongest tier of items in the game and are required to make the strongest tier, making them completely necessary if you hope to survive the harrowing boss fights to come. Diamonds are also components in Enchanting Tables, so they are the gate behind which all high-development gameplay is hidden.
Diamond is also the tier of tool that unlocks the Nether (if you're not a speedrunner, that is) since Obsidian cannot be mined without a Diamond pickaxe or higher. While Diamonds have limited use, similar to Netherite, they are far more essential when unlocking endgame items.
2 Iron
Iron is ubiquitous in Minecraft– while Diamonds are certainly the more iconic resource, Iron is going to be a part of every level of development. Iron basically makes up half of the important items you will use in the game; need to move liquids? Buckets. Need to make simple transport for yourself and mobs? Railroads and Minecarts. Need to upgrade to Netherite? That's right; Iron is necessary for creating the Smithing Table that unlocks the strongest tier of tools.
Iron is even key in the most basic Redstone automation, being in the crafting recipes for both Pistons and Hoppers. If you plan to develop your world to any extent that will make it easier to travel, fight, and farm in, Iron will be there no matter what.
1 Redstone
Redstone was the most difficult ore to place on this list. Redstone automation is completely optional and is not necessary to progress throughout the game. If you wanted, you could start a world and beat the Ender Dragon without ever touching a piece of Redstone. But the sheer potential of Redstone makes it undeniably the best resource to mine for in the game.
Redstone automation can make your life in Minecraft easy– there are farms for so many resources, and a good number of them require Redstone to build. The sheer usefulness of being able to ignore a whole part of the core survival experience, like mining, searching for food, and spending time traveling long distances for resources, is what puts Redstone over the top.