Dark Prismarine

Dark Prismarine is an upcoming stone-like material that only will appear underwater in ocean monuments. This block is a variant of prismarine block.

World Generation
Dark Prismarine is generated naturally in Ocean Monuments, where it encases the 8 Gold Block reward of the dungeon, and for some other decorative features, although this method is non-renewable.

Crafting
Dark Prismarine can be crafted with 8 Prismarine Shards and 1 Ink Sac, which is inefficient and requires a lot of shards, however is renewable, and the demand for shards can be met with a Guardian farm. A Squid farm is also recommended. Since both mobs spawn in water, you might consider building a mob trap that deals with both mobs. The guardians will zap the squid into non existence, and you can finish the guardian off with iron golem.

History
Dunkler Prismarin Prismarin sombre Dark Prismarine pt-br:Prismarinho Escuro