Deepslate uses the same color as stone on maps

The bug

Deepslate appears to use the same color as stone on maps, despite them being colored very differently.

How to reproduce

1. Run the following commands:

   /fill ~1 ~ ~1 ~10 ~ ~10 minecraft:deepslate
   /fill ~-1 ~ ~-1 ~-10 ~ ~-10 minecraft:stone 

1. Obtain an empty map, and fill the map
   There is no difference between the color of stone and deepslate on the map