This was a Vimmarkr, it was a tool used by Rune-Scribes to etch runes into objects. The Rune-Scribe would channel Orenda from their body into the vimmarkr and then draw out the runes they wanted to etch.
Rëwa began drawing runes onto the plates, these runes would flash briefly then he would move to the next one. After drawing runes on eight of the plates, he stretched out his hand and one of the twins handed him a blue fist sized jewel.
This was an azuri, it was the same jewel used in the creation of an Aurei. The jewel had the capability for Orenda to be stored in it, and then absorbed later.
It seemed that Rëwa had run out of Orenda after only etching eight plates.
Rëwa took the azuri in his hands and then absorbed the Orenda in it, which on took a couple of minutes. Then he continued with his work.