Minecraft wiki entry for Development_versions, associated text: Added deepslate variants of all ores, including iron, gold, copper, coal, diamond, redstone, emerald, and lapis lazuli.
Deepslate ore variants for copper, emerald and coal ore do not generate by default.
Takes twice as long to mine as normal ores.
Has the texture of deepslate replacing the normal stone texture.
Takes place of ores that generate in deepslate.
Can be used in blasting and smelting recipes like normal ores.