Item particle commands do not use blocks' item textures to create particles, instead, they use the block particles

How to reproduce

1. Run

   /particle minecraft:item minecraft:enchanting_table ~ ~ ~ 1 1 1 0 100 force

   → Observe that instead of using break particles of the enchanting table's side, it instead uses the particle that is formed when breaking the enchanting table. (Obsidian.)

This can also be seen with

/particle minecraft:item minecraft:player_head ~ ~ ~ 1 1 1 0 100 force