The Bug:

The map color of tuff blocks is too brown compared to the color palette of tuff blocks.

Steps to Reproduce:

1. Summon some tuff blocks beside you by using the command provided below.

   /fill ~1 ~1 ~1 ~9 ~1 ~9 minecraft:tuff

2. Obtain a map, use it, and look at the color of the tuff on the map.
3. Compare the color of the tuff on the map to the color palette of tuff blocks.

Observed Behavior:

The map color is too brown.

Expected Behavior:

The map color would be more gray, therefore matching the color palette of tuff blocks.

Code Analysis:

Code analysis by Avoma can be found below.

The following is based on a decompiled version of Minecraft 23w51b using Mojang mappings.

public class Blocks {
   ...
   public static final Block TUFF = Blocks.register("tuff", new Block(BlockBehaviour.Properties.of().mapColor(MapColor.TERRACOTTA_GRAY).instrument(NoteBlockInstrument.BASEDRUM).sound(SoundType.TUFF).requiresCorrectToolForDrops().strength(1.5f, 6.0f)));
   ...

If we look at the above class, we can see that tuff uses the map color "TERRACOTTA_GRAY". Other tuff blocks such as polished tuff and chiseled tuff simply copy the block behavior properties of tuff, causing them to use "TERRACOTTA_GRAY" as their map color as well.