Filthy Riven main in need of some help!

Alright I'll try to make this as quick and concise as possible. It's my first time posting on here so I'm not sure what to expect but here goes. Like probably a lot of you on here I really love this game and having been playing for a long time (just before the end of season 1). I've been playing since I was 15 and I am 21 now so this game has been a part of my life for a long time, and has had such a positive impact on my life (negative on my wallet for sure though).I started playing on the same patch Riven was released and coincidentally she was the first champion I ever spent RP on (along with Talon and Skarner) shortly after getting hooked on the game. Needless to say she's been my most played champion ever since.

Well anyway, the reason I'm here is because I wanted to get something commissioned as a symbol of this game's impact in my life. Not to long from now my family is planning a trip out of the country (United States) to visit some family members. We don't get to do this very often because of financial reasons but this is one of the times it is happening. Well my Godparents who I don't get to see often because they live out of the country are jewelers, and they are the ones I had panned to make me my symbol. My hope was to ask them to make me a necklace with Riven's Runic Blade (broken or whole) as the symbol/insignia. Since this is kind of a big deal for me, I want it to me well done and plan to spend some decent money on it I've been looking around as to what the dimensions of the blade actually are. So far I haven't found anything satisfying that I could use to scale down to what could be worn on a necklace. I tried asking Riot directly through a support ticket since I have never posted on the forums, and was promptly directed here. I'm simply asking for some help in figuring out some proper dimensions for the blade. I would really appreciate any help I could get with this, and I thank anyone who took the time to read all this as well. If all goes well and my little project actually follows through I'd be happy to get back to you guys and show you the finished product.