Add iron sulfide oak for shipwrecks in deep ocean biomes (and sulfur trees)

 Iron sulfide oak could be a black wood, maybe with dark blue and/or dark gray veins, darker than normal dark oak and definitely darker than warped wood.

Iron sulfide oak shipwrecks would be a rare variant for deep ocean. In real life, some shipwrecks have been found to be infused with sulfur compounds by anaerobic bacteria.

Iron sulfide oak tree generation should also be possible: a surface sulfur biome next to a plains biome should occasionally generate a patch of dirt and an iron sulfide oak tree. There would be no dedicated iron sulfide oak sapling; you would just need to plant an oak sapling in a surface sulfur biome and it will turn into an iron sulfide oak tree.

Other possible uses:

• The suggested color palette would go pretty well with skulk, so iron sulfide oak could be added to the decor of ancient cities.

• Cave braces in mine shafts that intersect with sulfur cave biomes could be made of iron sulfide oak planks and fences.