Japanese Name: Amy
Element: Ice
Birthday: Sept. 10, 1976
Sign: Virgo
Blood Type: A
Favorite Colour: Aquamarine and Light Blue
Favorite Animal: Cat
Favorite Gem: Sapphire
Favorite Food: Sandwiches
Least Favorite Food: Yellow-tailed Tuna
Favorite Subject: Math
Least Favorite Subject: None
Strong Point: Calculating
Hobbies: Reading, playing chess
Dislikes: Love Letters
Dream: To become a Doctor

Ami is a very smart girl that lives with her mother, she has a dad but he's a painter and only sends her paintings, in the Manga it says that she's a very rich girl, in the Anime they don't even show her house, her dream is to because a doctor, like her mother, that why she's very smart.
Sailor Mercury appears in the Sailor Moon Series, when she first when to Usagi school and appeared at the highest schools exam score, that was when Usagi notice that she was going to be in her class. Usagi told Luna what great Ami was, and that she think that Ami was taking her studies to hard.
Usagi went with Luna to see if Ami was going to by fine after her big exam at school, but in the exams Ami was attacked, Mercury's sing appears at her forehead and Luna notice that, so Usagi transformed, Luna give Ami her transformation pen, and told her to scream, "Mercury Power, Make Up!" So she transformed into... Sailor Mercury, the Senshis with the power of Water, or Ice (what ever)

Mercury's second form, her Fuku does not change, what does change is her transformation phase, and she receives some new Powers.
With new transformation phase, "Mercury Crystal Power, Make Up!" she transforms into Super Sailor Mercury.
This is the third and the last stage of Sailor Mercury, Super Sailor Mercury.
In the Anime, it is Pegasus that give her, her new Powers, in the Manga, it is a small version of her that give her, her new Powers. With a new and better Fuku and powers that she gains she becomes more powerful...
Sailor Star Mercury or eternal Sailor Mercury only appears in the Manga, and is the final and ultimate form of her, that we see, and appears in this form in the Stars arc.
In the Manga, after defeated Nehelenia, their Guardians appear to each of the Senshis and they turn into Princesses. The Guardians told them that it is time for another change, and they transform into their final forms by using their power of their mother star castles, "Marina Castle of my mother star Mercury!" and she transformed...
But she actually scream, "Mercury Planet Power, Make Up!"

During the Silver Millennium, Sailor Mercury is guardian of Princess Serene, she is also a Princess, Princess Mercury, who has her own Castle, Castle Marina
The name of her castle, Marina has to do with water. The word 'marina' means: A boat basin that has docks, moorings, supplies, and other facilities for small boats.