In its camouflaged form, the brooch looks like a peacock with the shape of a peacock's body and head at the bottom center and with nine light sea-green tail feathers coming out from it.
When charged, the brooch changes from nine feather segments to five. Its main color is dark blue, while the crystals on the top of each segment are pink. The lower part of the Miraculous also changes from the body of a peacock into a single tear drop.
The Peacock Miraculous grants its wielder superhuman characteristics of speed, endurance and strength.
The Peacock Miraculous grants its wielder the ability to bring someone's despair/emotions to life in the form of a protector who is resembled as a beast. The cause of this is mostly to get the target out of a hopeless situation. To achieve this the user has to take a feather out of their Tool (which is a hand fan in this case), charge it with energy and send it on its way (through a blown kiss) to the person who has to be protected. What follows is that the feather phases into an object which the target owns, possessing it, thus making it possible for the wielder to summon the ally and to create a telepathic connection between themself and the person they want to save. The wielder of the Miraculous also has the power to renounce the beast they created, making it disappear as fast as it had appeared in the first place, and to purify the feather they originally charged with energy.
Peacocks are a symbol of integrity, vision, and vibrancy.
In the theme song, the Peacock Miraculous briefly appears in its disguised form inside the Miraculous jewelry box.
Inside Gabriel Agreste's safe, it is placed in front of a picture of Emilie Agreste.
As noted during an event with the writers, it is "weird" that Plagg doesn't recognize it when he and Adrien look in the safe in "Volpina".
It is confirmed that the jewel stored in the safe in "Volpina" was not the real Peacock Miraculous, merely a copy created by Gabriel Agreste. However, the Peacock Miraculous shown in "Mayura" is clearly the real Miraculous, shown by it being in its charged state, which is activated by having a kwami in its Miraculous.
As seen in "The Collector", the Miraculous spellbook has a different depiction of the Peacock Miraculous. In the book, it appears to be blue with five tail feathers.
In "Mayura", the Peacock Miraculous uses the five-feathered design when inhabited by Duusu, and the nine-feathered design when in its disguised form.
The Peacock Miraculous has an adverse effect upon its holder when used. Though it could be because it is damaged, according to Gabriel Agreste. After she detransforms, Nathalie is coughing and fatigued as result.
It is the only known Miraculous that is "damaged". How this happens is yet to be revealed.
The Peacock and Butterfly Miraculouses have rather similar powers, including charging small things with magic to infect objects of specific people and telepathic communication with them.
Interestingly, both Miraculouses are considered brooches which may cast light on the fact that they own such similar powers.
Coincidentally, both are currently kept by Gabriel Agreste.
They are also both currently used for evil purposes.