The survival update added a lot of things, but also made ores harder to find.
Where to find ores
Turns out, all they did was change the way the voxel appears on the surface.
You won’t be able to find ores by looking for dark patches anymore.
Instead, you should look for subtle, light discoloration in the ground to find ore veins.
It’s still difficult to find these patches just because they’re so hard to spot, especially on noisy grass or rock terrain, but if you happen to spawn in a snow biome, they’re much easier to see.
In the snow, you might be able to notice yellow spots. This isn’t the sunlight, this is the ore patch.
It’s a lot more obvious when the snow is in the sunlight’s shadow, too.
Scroll out your view with alt+mousewheel to get a good picture of the terrain, and you might be able to find these patches easier.
But what about other spots?
You can thank u/Gatonom for these images.