Concrete is a fairly tall Gem, her upper body wider and more prominent than her lower body. She has prominent lips, curly short hair, and gray skin.
She wears a light gray body suit, a dark underline on the upper half of it. Her hands and feet are covered in black gloves and boots. Her gemstones line her upper chest horizontally, shaped similarly to the gemstones from the Elements of Harmony.
She, as a cluster Gem, was found by Diopside in the White Diamond Space Station while the Crystal Gems were trying to get Pearl and Aquamarine out. In her clustered state, she attacked Diopside, which made Diopside "shatter" her. She was brought back to the others and Jade managed to revive and put her back together. She was presumably brought back to Homeworld when they left.
- While not an official character from the Steven Universe series, she was one of the scrapped characters, in similar vain to Budgerite.