Can't /testfor Prismarine Crystals or Shards

I am making a rogue-like dungeon adventure world, and to summon the boss, I am trying to use a command block that uses /testfor @e[type=item,name=prismarinecrystals] but the command does not find the item. I have tried the command in multiple command blocks, different servers and worlds, different settings, and I can't figure out what the issue is. I know the command works, because I can do it in Java no problem. So I don't know if its just not an implemented command in bedrock yet, or if its just a legitimate coding error where it was just not added in. Any assistance would be great