Prismarine

"I picked Prismarine because 1) it sounds good, 2) it references water with "marine", 3) it references its "shimmering effect" I hinted at with "prism", and 4) it doesn't really mean anything in the real world."

- Jeb about the name

Prismarine is a stone-like material that only appears underwater in ocean monuments.

Prismarine bricks are a decorative form of prismarine with a sawtooth-edged brick pattern.

Dark prismarine is a decorative form of prismarine; it is dark, with a tight grid pattern.

Obtaining
All types of prismarine can be mined using any pickaxe to drop itself. If mined without a pickaxe, the block will drop nothing.

Natural generation
All types of prismarine naturally generate as the main blocks making up ocean monuments. Normal prismarine and its bricks are found in large amounts due to the size of the structure. Prismarine bricks make up the 23 pillars below the monument, and appear decoratively throughout the structure. Somewhat more rare is dark prismarine, which encases the 8 gold block reward of the dungeon, and appears in fewer decorative features. Normal prismarine can additionally be found in underwater ruins.

Crafting
Each type of prismarine can be crafted using varying amounts of prismarine shards, and an ink sac in the case of dark prismarine. All of these resources can be obtained from underwater mobs.

Usage
The only current usage for prismarine is decoration or as a high blast resistance building block.

The normal prismarine is uniquely useful for decoration as it has an animated texture. The cracks in prismarine slowly cycle in color through aqua, green, purple, and indigo. The full animation for the prismarine texture changes color 22 times in an irregular sequence before the whole pattern repeats; this takes 5 minutes and 30 seconds.

Conduit power
Prismarine and prismarine bricks can be used to activate a conduit by building a structure around it. By doing this, the conduit will emit the "Conduit Power" effect in a certain radius, depending on how many blocks are used to power it. Sea lanterns can also be used for this purpose, while dark prismarine cannot.

Data values
Prismarine has an ID name of  and an ID number of 168. It uses its block data and block state to determine which variant of prismarine is displayed.

Trivia

 * The name "prismarine" was created by Reddit user AjaxGb during a naming contest, where Jeb was looking for a name for the block.