The black silk tie could symbolize elegance and sophistication in the Twilight fanfiction. Vampires are often associated with these traits, and a character wearing a black silk tie might be seen as a more refined or powerful vampire within the story.
One possible plot could be a character in the Twilight universe wearing a black silk tie to a formal vampire gathering. It could add an air of mystery and elegance to their appearance, and perhaps be a symbol of a new status or role within the vampire society.
The black silk tie can be used to set the mood. If it's a period - piece fanfic set in a glamorous era, a black silk tie can add to the overall elegance and sophistication of the setting. Writers can describe how it shimmers in the light or how it's tied in a unique knot to give more depth to the scene.
One possible story could be a character in a fanfic wearing a black silk tie to a formal event and it becomes a symbol of mystery. Maybe it catches the eye of another character who is intrigued by its elegance.
In some fanfictions, the hair tie is described in great detail. Writers might focus on its texture, like if it's made of silk or something more rustic. This can add to the overall atmosphere of the story. If it's a silky hair tie, it could give a sense of elegance and refinement, while a more rustic one could suggest a connection to a simpler or more earthy part of Bella's life.
I'm not sure of a specific one off - hand, but you could try searching on fanfiction - specific websites like Archive of Our Own. There might be some hidden gems there that center around this unique concept of a twilight black hair tie on the wrist.
Another possibility is that it's related to the overall theme of the fanfiction. If the story has a lot of dark or mysterious elements, the black hair tie could be a small detail that ties into that. It might be a clue for readers, something that will be revealed later in the story to have a greater significance, like being part of a magical or supernatural object.
Some fanfictions may feature the black hair tie as a sign of a secret society within the Twilight realm. The character with the hair tie on their wrist is a member, and they have to keep it hidden from the other factions. The story could revolve around the secrets they keep and the danger they face if discovered.
Perhaps in the fanfiction, the black hair tie on Jade's wrist is a clue to her past. She has amnesia and the hair tie is the only thing she has from her previous life. As she begins to investigate, she meets various characters who either try to help or hinder her in uncovering the secrets associated with the hair tie.
Perhaps the black hair tie is a reminder of a past love. Felicity is constantly haunted by the memories associated with it. She meets someone new in the fanfiction, and the presence of the hair tie creates a conflict as she tries to move on from her past while still holding onto this memento.