Sardonyx's room is a virtually empty "room" in a blank white void. Sardonyx herself states that her room is infinite but it can only exist so long as she does as well.
Similar to Rose's Room, Sardonyx can manipulate her room to her will. In "Know Your Fusion", she was able to craft her room into a late night talk show; complete with props, show games, curtains, and a laugh track that acts as her audience. She is also able to manipulate the lighting in the room, being able to completely engulf it in darkness and only a spotlight showing anything in the room. She is also able to show clips of previous episodes, via a drop-down screen next to her, and play voice clips of other characters, such as Sugilite.
- In "Know Your Fusion", it is revealed that Sardonyx's Room is only available when she is actively fused.
- When Sardonyx's room is activated, the Temple Gate turns into a curtain.
- When Sardonyx is walking around in this room, a spotlight is shown to be following her. She is able to turn it off, similar to commercial breaks during comedy shows.
- Sardonyx's room is the only room in the temple shown that does not correspond to how the gem is made or looks like.
- Sardonyx's room does not immediately cease to exist when Sardonyx unfuses, but rather loses its darkened effect, locks into whatever stage effect was active when Sardonyx unfused, and starts slowly collapsing. The exit door also experiences physical glitches similar to that of a damaged gem (e.g. Amethyst in "An Indirect Kiss") during this process.
- The existence of Sardonyx's room implies that rooms for all of the known fusions of the Crystal Gems exist as well, including Smoky Quartz, Rainbow Quartz, Opal, Sugilite, and Alexandrite (although the lattermost two may have physical difficulty accessing their rooms due to their sheer size and the physical limitations of the Beach House).
- By extension, it also implies that Ruby and Sapphire each have their own, separate rooms when unfused from Garnet.