The fusion has dark orange-yellow with mahogany patches all over the body as a result of the corrupted gem monster. She has long light-ivory/dark white colored hair which comes from Jasper that extends down tot he midriff. The gem has four arms and has horns all over its body with Jasper's face and sharp teeth.
The fusion gem's personality is unknown due to the short amount of time it had, but it appears to have been very unstable and violent being a fusion between Jasper and a corrupted gem. The gem appears to lack any form of strategy as shown between the fight between the gem and Smoky Quartz where it charged straight at her and without any strategy. This may stem from the lack of self-awarness and control that the corrupted gem had and how it couldn't cooperate with Jasper's tactical mind.
In the Beta Kindergarten, Amethyst, Steven, and Peridot had spotted Jasper and found out where she had been keeping her collection of corrupted gems and how she had them caged in the spots where other Quartz soldiers had previously been made and came out of. After a fight between Amethyst and Jasper with Jasper getting the upper hand, Steven and Amethyst fused to create Smoky Quartz and they began to beat back Jasper. In a desperate attempt at victory, Jasper ended up fusing with the blue north gem monster and formed the unknown quartz fusion. The fusion began to attack Smoky and had a brief period of victory, but was easily and quickly overwhelmed and defeated and de-fused shortly afterwards which lead to Jasper's corruption.
The exact full-range of abilities is unknown but the gem appears to be very strong judging by its size and how physically strong both gems are. The fusion also had sharp claws which came from the corrupted gem and was very strong.
- It's unknown if the fusion can speak, as her few utterances have been animal-like growls, cries, and one laugh, presumably from Jasper.
- The Unknown Quartz Fusion is the first fusion between a normal Gem and a corrupted Gem. She is also the first fusion involving a corrupted Gem at all.
- After they defused, Jasper became corrupted as well and slowly degenerated into a similar Gem monster – notably, the corruption matched the corrupted Gem's color palette, not Jasper's (showing that a Gem can be corrupted just by fusing with a corrupted Gem).
- Although the corrupted Gem monster's gemstone was a hexagon, it is shown to be round while fused. This was most likely an animation error.