Magnesium Deepslate Ore

At negative Y levels, in place of coal, a new ore called Magnesium should spawn in the deepslate. Magnesium works just like coal in many circumstances. It could be used as a fuel source as efficient or slightly more efficient than coal. Magnesium would not have a normal stone ore texture, as it only spawns lower down, below y=0. The biggest upside of using Magnesium is for torches. Magnesium torches emit the same light level as normal torches, but they are a bright white. Magnesium torches are also perfect for the new caves because Magnesium fires do not burn out underwater. This would allow you to place Magnesium Torches underwater. They would emit the same or slightly less light level than normal underwater and would waterlog. Adding Magnesium Torches that do not burn out underwater would be really helpful in exploring the new aquifer generation, and could help prevent the spawning of drowneds, as well as generally light up the caves.