EDIT 9/3/17: I'm changing a few things up, if it's in bold then that means I'm changing it
I was up last night at 3:00 AM and thought "Why not a Steven Universe AU" or gem AU. I got inspired by milkysqueak 's book to do this so check out their stories! It's really good. So it took me a while to do named who is who and here is what I think:

Lafayette
Gemstone: Citrine
Weapon: Estocs
Gemstone location: On his back, I'm not gonna make him a fusion of James and Thomas cause I want to make him his own gem

Hercules
Gemstone: Violet Tanzanite
Weapon: Rocket Launcher (probably not a big one though)
Gemstone location: Shoulder

John
Gemstone: Blue Hemimorphite
Weapon: Sharp Tonfas
Gemstone location: Center of forehead

Phillip
Gemstone: Emerald, the same as Alex
Weapon: His dad's shotgun and bubble (Eliza thinks it's too dangerous for Phillip to use it)
Gemstone location: Center of chest

Thomas
Gemstone: Andesine (the red one)
Weapon: Axe
Gemstone location: Palm of left hand

James
Gemstone: Jade
Weapon: Spear
Gemstone location: Palm of right hand

Sphene (James and Thomas fusion, let's just keep them as sphene cause I'm bad at names)
Gemstone: Sphene
Weapon: Halberd
Gemstone location(s): palm of right hand, palm of left hand

Eliza takes care of Phillip from time to time (and doesn't get along with John that much)

Theodosia (the kid) is Phillips friend, so basically Connie in the story
I wanted to make Burr a gem but then I was like "Wait who would be Theodosia's parents"

Alex (in some oneshots/stories Alex will be "alive" and Phillip won't exist..yet)
Gemstone: Emerald
Weapon: Shotgun, bubble
Gemstone Location: Center of chest

Edit: I'm so stupid I forgot Washingtons gemstone
IM ADDING WASHINGTON
Gemstone: Spinel
Weapon: Sword combined with a gun, because he is that much of a badass general
Gemstone location: left eye

Now they aren't exactly the characters and have the same gemstone.  They have their own personality's, gemstone, and their weapons may be the same as the show but with different colors.  Also their abilities will be the same too (kinda), and their gemstone location may be the same as the show.
I might do one-shots
Sorry for not putting pictures, I can't draw very good

✨PLEASE READ THIS, YOU NEED TO KNOW THIS✨

Okay so here's the thing, Washington is the leader of the Revolutionary Gems and Alex is his right hand man (what else would he be honestly). The gems moved to earth to start a new life being free, but still fighting. Everything is going dandy until Alex falls in love with a human, Eliza, and starts spending more time with her.

Let's just say that Eliza wants to have a kid and life with him, but here's the thing..

Eliza can't reproduce (can't make babies)

So Alex insists he takes his own form to create Phillip to make her happy. At first Eliza thought he was joking so she in-a-sort-of-way said yes.

But after discovering that he was in fact not joking she quickly declined, but it Alex did it anyways because he NEVER LISTENS AND HE JUST WANTED TO MAKE HER HAPPY. Everyone was devastated, yes even Thomas cause they were a sort of "good friends". John honestly blames Eliza, but never says it.

So they are left with a smol little baby who they helped him grow up with Eliza.

Btw, they chose "human" names to feel more adapted earth, and I honestly don't know how to make Lafayette say that he wanted like 11 names..