Just had an idea that felt worth sharing as a suggestion. I did some searching and didn't find a lot on the subject.
DISCLAIMER: THIS IS NOT FOR CHEATING AND WOULD NOT LET YOU SEE ORES LIKE MAGIC. See below.
Xray Goggles or an Xray mode for nano or, more likely, quantum helmets. The idea has its share of balance for power as well as limited abilities. In other words, you wont just be able to see all the ores underground and go right for that uranium and diamond cluster.
The Xray specs (in whatever form they would take) would consume energy based on the level of power being consumed. Each tier of energy would be able to see through more objects based on their density. For example dirt and sand would be of the lowest density and thus would require less power to see through more layers than stone or cobble. Some things, such as obsidian and lava would be nearly impenetrable to most of the settings on the Xray device, however by bypassing the safety limiter on the device, you can even see through the most dense objects at the risk of deadly radiation poisoning, and if left on for too long would even set yourself on fire from the amount of excess heat generated. Obviously ores are more dense than stone, and if you're nearby, say, an iron vein for example, you turn the Xray tool on and looky there, some iron. The effect that is created is a field of view around Steve that just has no blocks visible for a limited range when not blocked by dense stuff. Within that field will be more dense objects. The closer those objects are, the more likely they would be invisible as the power of the device is higher at close range. By that logic, you may only see the back half of a coal vein, or even a single block of iron if any at all if you're too close. Also by that logic, you may be able to see through stone into a whole canyon or cave and any exposed ore in there, leaving luck to play the same role in mining as it always has.
The purpose of this tool isn't just to hunt down all the good ores, I just wanna make it REALLY clear that this isn't some OP tool that will remove the need for hard mining or running around with the miner tool if you're just trying to be lazy. It's purpose is more for utility. Get that one block of iron that you missed on a corner of a vein, find that lava you can hear but can't find or know if that strip mine is in fact totally stripped.
The function of the tool itself might be easy enough to work into the game. A simple customizable text config like the miner could set density values and allow ores from other mods to be added. The range itself could be as simple as a loss of power at a fixed amount per block away from eye level, and if the power versus loss over distance falls under the density value of an object in view, it leaves it visible. I'm not sure about the actual removal of the blocks in range or how that would work, I know very little about what is and isn't possible in Java or Minecraft's code.
Positive feedback would be cool. Feel free to message me if you wanna share something that you don't wanna talk about on the board.