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, just like in comedy shows whenever they are on commercial breaks.
- Sardonyx's room is the only room in the temple shown that does not correspond to how the gem is made or looks like.