Resource Pack replaces all ores in the Overworld, making them less visible in the environment. However, they can still be seen and told apart from each other, but it will be more difficult than usual.
Changes the gameplay, requiring you to venture deeper underground and even become a bit of a 'mining archaeologist'.
With these new realities, you need to upgrade your mining skills in a new way. Examine each block carefully, determine where the ore is likely to be, try to feel it. New senses come into play: intuition, perception, the thirst for mining.
Wandering through dark caves with low brightness, carefully or hurriedly placing torches, glancing from one block to another. At some point, you may start thinking that everything around you is ore. Isn't that the true path for a real mineral hunter?
And then, returning home with a stack of iron ore will feel truly blissful like never before.