Companion NPC's do not pick up the gem stones that they harvest from deposits.
To Reproduce:
Equip your companion with a Pick and finding a gem stone node (i.e. quartz, amber, etc.).
Allow the Companion mine the node.
Once the Node has broken , they will leave the raw gemstones where they fall.
Expected Result:
Similar to Rocks, and providing they have room in their inventory, the companion should pick up the gem stones that drop from the Node
I feel that the NPCs should pick up anything that they already have in their backpack, to include drops like Gunpowder, meat, hides, bones, chitin, etc. This would not be an automatic responce to drops, the NPC would only pick up what you have already given them.