I Fucking hate Tumblr the pressure to make a Gemsona was too much!
Anyway this is Sunstone, he prefers male pronouns. He is a giant dork full of energy which weapon is a firearm (literally it shoot heated energy instead of bullet, because SUNstone get it? HAHA!). HIs vision is awful which is why he wears a visor. Sunstone's gem is located on his chin.
For backstory I presume he was a ally of Rose Quartz but got defeated during the conflict? I don't know!
Anyway it was quick thing to do, I think I emulated the design style of gems alright :3. So enjoy!
Steven Universe belongs to Rebecca Sugar