Oh by the way I found out about Aria's symbol: She's the secondary symbol for fire - The Untamed. Interesting, I was poking around and I think I found other Metal based elemental statements for Alchemical-Chemistry transfer meanings.

Jaden - Iron - The Guardian

Aura - Helium - The Judge

Aria - Hydrogen - The Untamed. 

I believe I have found some others pertaining to chlorine base elements - gases, and something for Radiation. I'm still looking but I'll let you guys know, if you want me to tell you that is. I'm not sure you want to know something that's from a psudo-science. I just kind of found it interesting.