This is one curious item. And it makes even more curious items.
Carrying a primal charm provides a slow trickle of vis to recharge your wand, and a certain amount of entertainment. It is also used heavily in advanced crafting.
The Primal Charm is made on the Arcane Workbench. It requires 25 vis of each of the primal aspects (so you do need something better than the "starter wand"). The recipe does not need to be researched.
While carried in your inventory, the Primal Charm will occasionally drop an "aspect orb" of a random primal, which is essentially a loose point of vis. If you have a wand, scepter or staff in your hotbar (which is not full in that aspect), this will be drawn toward you like an item, and when picked up will be added to your wand's storage. While this only gives a single point at a time, it happens fairly often, and in the early game it can help a lot with recharging your wand while you're doing other things.
The "hovertext" seen while it is in an inventory is also ever-changing, and frequently amusing.
The Primal Charm is also used in the crafting of many other items: Staff cores (including the Staff Core of the Primal), scepters, Vis Storage Amulets, the Runic Baubles, the Primal Wand Focus, and more.
When hovered over, the Primal Charm may occasionally show an orange tooltip under it. The tooltip is shown for a few seconds before it disappears.
Here are the several tooltips and the events that occur along with it:
"Wait, did it just show a seventh colour?"
This shows when the Primal Charm flashes to Orange before returning to its original pattern.
"You think you hear whispers"
This shows when you have gained warp and will show more often the more warp you have.
"It seems to be leaking"
Shown when the primal charm drops an aspect orb.