Sailor Mercury Special Powers and Items

In her first Senshi uniform, Sailor Mercury demonstrates her power over water withShine Aqua Illusion.

In the manga, Ami can dowse without any aids. Otherwise, she is not shown using any special powers in her civilian form, and may not be able to. She must first transform into a Sailor Senshi by raising a special device (pen, bracelet, wand, or crystal) into the air and shouting a special phrase, originally "Mercury Power, Make-up!" As she becomes more powerful and obtains new transformation devices, this phrase changes to evoke Mercury Star, Planet, or Crystal Power. In the anime, Sailor Mercury's transformation sequence evolves slightly over time, whether to update the background images or to accommodate changes to her uniform or a new transformation device, but all of them involve a stream of water which she whirls around her body as she spins, forming her outfit with a ripple effect.
Sailor Mercury has the power to manipulate water. For the entire first story arc, she uses her powers only to create dense clouds of mist, chilling and blinding the enemy while her allies prepare more direct attacks. In the manga she usually does this without speaking, while in the anime it is given the name Shabon Spray. In the updated renewal manga, this power is renamed Mercury Aqua Mist to match the live-action series, in which she has an offensive beam attack by that name, capable of destroying weaker enemies. She uses a total of five attacks in this series, most of which are variations on the first.
Sailor Mercury's first major offensive attack is Shine Aqua Illusion, introduced in the second story arc, which can be used as a simple projectile, to freeze the enemy in solid ice, or to create a defensive barrier. Aside from variations on her other powers (mostly improving their strength with the addition of "Freezing" or "Snow"), her next named attack is Mercury Aqua Mirage, used during the third arc of the manga and again in the special side-story "Ami's First Love" (manga and anime). Her final and greatest power comes in the fourth story arc, when she takes on her second Senshi form (Super Sailor Mercury in the anime). At this stage she acquires a special weapon, the Mercury Harp, and with it Mercury Aqua Rhapsody, which is her primary attack for the duration of the story. In the anime Mercury gains the harp deep within her subconscious. The manga took a different approach with the Mercury Harp making it more of an item rather than a harp formed due to the attack. Furthermore Sailor Mercury gained the harp through her power guardian. In the manga the Mercury Harp, as well as the other inner senshi's weapons have their own "wills" and can even speak and give input.
In addition to her own powers, Sailor Mercury has more non-magical items than any other Senshi. Early on in the series she makes frequent use of an extremely powerful "Micro-miniature Super Computer" that enables her to make special calculations, scan her surroundings, track the movements of allies as well as foes, and determine her enemies' weak points. The computer works in sync with her Mercury Goggles, which analyze the area around her and display information in front of her eyes and on the Computer. The visor may be a hologram of some sort; it materializes across her face when she touches her earring. The manga sometimes shows her wearing a small microphone connected to her earring, which she uses to communicate with Luna at the Senshi hideout during the manga's first arc. All of these devices gradually fall out of use as the series progresses. In the live-action series, like most of the other Senshi, she receives a tambourine-like weapon called the Sailor Star Tambo. She is one of two Senshi to use it for a named attack (Mercury Aqua Storm), and later can transform it into a sword. She also creates swords out of water, both as Sailor Mercury and as Dark Mercury.
In the manga, the Mercury Crystal and Mercury Harp are among her most significant magical possessions. The former is her Sailor Crystal and the source of all of her power, which becomes especially important in the fifth story arc. The harp's form is actually that of a lyre, a stringed instrument smaller than a harp, which according to Roman myth was invented by the god Mercury.

Sailor Moon Special Powers and Items

Sailor Moon's pre-battle taunt pose, an iconic symbol throughout the series:
"In the name of the moon, I shall punish you!"

Usagi is not shown using any special powers in her civilian form. She must first transform into a Sailor Senshi by wearing a special device (usually a brooch) and shouting a special command, which activates the device. Her original transformation command is "Moon Prism Power, Make-up!" She gains a new basic transformation sequence for each of the five major story arcs. In her basic form, the command changes as she becomes more powerful and obtains new transformation devices, evoking "Moon Crystal Power" and later "Moon Cosmic Power". A transformation into Super Sailor Moon initially requires her to already be in Senshi form and to use an additional item (called the Holy Chalice/Rainbow Moon Cálice) as well as the command "Crisis, make-up!", but in the anime this saps her strength. For the fourth story-arc she gains the ability to transform directly into Super Sailor Moon via Moon Crisis, and in the fifth arc becomes Eternal Sailor Moon with Silver Moon Crystal Power in the manga, or Moon Eternal in the anime (and once in the manga). At first, she is required to be in her Super Sailor Moon form, in the anime, to become Eternal Sailor Moon, as the upgrade to her Brooch is temporary. When facing off with Nehelleina for the final time, the Brooch is permanently upgraded allowing her to become Eternal Sailor Moon directly.
Most of Sailor Moon's anime transformations involve the use of shiny red or pink ribbons which fly out of her brooch and form her uniform. Feathers and wings also figure prominently in some sequences, particularly the transformation into Eternal Sailor Moon. When she de-transforms, the ribbons reappear and unravel from around her body and go back into the brooch. Usually the clothes she was wearing before she transformed reappear, but if her de-transformation is forced, she may be left naked with the ribbons hanging loose around her body. She also has the Disguise Pen, which allows her to take on a human disguise by saying "Moon Power!" This is used very frequently in the first story arc, but is only mentioned once during the third arc.
As the protagonist and leader, Sailor Moon has the most special powers of any character in the series. Her physical attacks, usually one-offs and not always successful, include Sailor Moon Kick and Sailor Body Attack, as well as the occasional use of her hair pins as projectile weapons. In her very first battle, she cries in terror and the red hair pieces on her odango amplify the sound waves, doing damage to the enemy. Her odango ornaments can also be used to hear faraway sounds, although this is rarely ever used.
General magic attacks are her most common type of power. In each adaptation of the series she can remove her tiara and turn it into a throwing weapon, which is her first major attack and which she continues to use on occasion far into the anime series. In the anime she demonstrates the ability to control the path of her Tiara, and once, to enlarge it and then shrink it around the enemy, ensnaring them. In the manga, a powered-up tiara enables her to attack with Moon Twilight Flash while in the live-action series this move requires an item called the Moon Stick and is her primary attack, though she also sometimes uses unnamed beam attacks. In the manga and anime she only uses the Moon Stick to perform Moon Healing Escalation and return possessed humans to their normal selves; Luna says in the anime that this item belongs to the leader of the Sailor Senshi. In the anime, she once uses her tiara to purify a group of possessed people, and in the live-action series she can heal others without any incantation.
One cannot always distinguish between healing or purifying powers and attacks, as the monsters of the day in the series are usually created by corruption of an object or person. Sailor Moon has one or two primary attacks per story arc, most of which require a unique rod or wand, and in the original anime, each of them causes the target monster to shout a phrase and revert back to what it was made from (or to dust). These primary attacks are: the first series' Moon Healing Escalation, the second series' Moon Princess Halation, the third series' Moon Spiral Heart Attack and Rainbow Moon Heart Ache, the fourth series' Moon Gorgeous Meditation, and the fifth series' Starlight Honeymoon Therapy Kiss and Silver Moon Crystal Power Kiss.
A handful of powers come up only once and in critical situations; often the common repeating powers in the anime are only one-offs in the manga. In the anime, Sailor Moon uses her transformation command when battling Queen Metaria and when turning the Ayakashi Sisters into normal women. She says Moon Cosmic Power when struggling to destroy Pharaoh 90, and at the end of the series uses Silver Moon Crystal Eternal Power to fight Chaos.
Sailor Moon can be temporarily powered-up by the other Sailor Senshi lending her their powers, as shown in the climax of the Sailor Moon R movie and multiple times throughout the series. She also often attacks in tandem with her daughter, Sailor Chibi Moon, and, at critical moments, receives power from individuals such as Luna, Queen Serenity, her future self, Mamoru, ChibiChibi, and others.
By far, Sailor Moon's most important item is the Silver Crystal, which is the "holy stone" of the Silver Millennium. It figures significantly in the first, second, and fifth story arcs, as it is the proof of her identity as the Princess and the source of her power. It eventually evolves into the Silver Moon Crystal.
In terms of personal items, Sailor Moon attaches particular importance and sentimental value to her gold locket. In the anime it plays a version of "Moonlight Densetsu", the opening theme for the series. Sailor Moon finds it after it is dropped by Tuxudo Mask. It is a relic of their past lives which she had given to him as a gift. Sailor Moon uses this locket in moments of sadness caused by her separation from Mamoru.