Today I want to talk about Tsukuyo's hair. Tsukuyo has chest-length purple hair, that is dark enough to look like black hair. Her hair is two-tone, with her exterior being the aforementioned dark purple, but her interior is an almost golden blonde. Interestingly, her ears are entirely dark purple. If they were instead yellow on the inside, then I would have guessed at her painting her hair to be more ninja-like in order to blend in better. I'm not so sure on that theory now, since she wouldn't have any need to do that to the inside of her ears (along with that potentially being very dangerous). Hair doesn't get darker, and instead shines, when light is on it- and Tsukuyo's hair does indeed have light near the top. Somehow, I don't think it's the Mystic doing this, either. It could be possible if we assume that it shapes the student based on desire, but that is immediately and soundly refuted by Tsukuyo wanting to be shorter. That leaves her being born with it, which is certainly possible, and shows that little kids have no taste because her hair is very pretty because of the dark purple and golden colors coming together- the gold standing out more, since it is both complementary and the brighter color. Her hair covers her right eye with rather short bangs, which, going by her ninjutsu research club pin, is one of her key identifying features. It does give her a stealthy look, since that eye is there, but it's hidden, like she might be planning something. It's the sort of look that has a ninja's stealth, and an honest girl, brought together.
Tsukuyo's tree costume doesn't have a sprite, according to the wiki. However, it is an iconic part of her, so it must be discussed. Her disguise actually hides her golden hair, only showing the bangs, one eye, ears and purple hair. It might be inaccurate if you really look at it, but it's actually quite good at concealing Tsukuyo herself. The scarf also showing on the disguise is a nice touch. As a whole, it seems that her right side is more "closed" and hidden, ninja-like, while her left is more "open" and honest, Oono Tsukuyo. A rather literal representation of being Michiru's right-hand ninja.
Considering Tsukuyo's timid nature, and being a ninja, as well as having a hobby for hiding, she doesn't strike me as a girl who has a particularly strong scent to her hair, since that could reveal her. It would probably smell like the moonlit Hyakkiyako on a late spriing evening- a faint cherry blossomo scent, getting more distant as time goes on.