Coal Ore Block Texture (1.17)

     While there are very good reasons for ores to have different textures, particularly for those with colorblindness, coal ore and diamond ore should share the same texture.

     One ore is the first ore many encounter (given how common it is), and the other ore is the most sought-after ore in the Overworld, and these two reasons make their shared texture thus far a part of the iconic representation of Minecraft. Furthermore, in addition to relative spawn heights, these two ores sharing a texture solidifies their relationship as two different manifestations of the same element.