Prismarine Crystals

Prismarine Crystals are items that can be obtained by defeating the Guardian mob.

As a drop from Guardians
Prismarine Crystals are dropped by Guardians or Elder Guardians. 0-1 are dropped each time.

The drop only happens if the raw fish drop fails. Looting I gives the best chance (27%).

From sea lanterns
Prismarine Crystals can be dropped by sea lanterns, and 2-3 are dropped each time. This can be increased to 5 with the fortune enchantment.

History
Cristaux de prismarin pt-br:Cristais de Prismarinho 海晶砂粒