Amulet of Avalor

The Amulet of Avalor is a mystical and magical amulet that bestows upon its wearer magical abilities of her own. According to a book of magic:

"With each deed performed, for better or worse, a power is granted, a blessing or curse."

This said, it can be assumed that the wearer's good deeds ignite magical abilities whereas misdeeds cause the wearer to be cursed. Also, according to Cinderella, the Amulet connects all of the princesses that ever existed.

The Amulet was a welcoming gift from King Roland II to his new stepdaughter, Sofia.

When Sofia helped a baby bird back into its nest, reuniting it with its mother, the Amulet blessed her with the power to talk to animals. After that, she has not been blessed by the Amulet since, likely because her other deeds have a tint of personal gain in some way or were rigged.

The Amulet curses reflect the bad deeds performed. Such as when Sofia bragged about singing she started croaking making her unable to do so. Only by apologizing and making things right can the curses be lifted.

The Amulet also earns Sofia an enemy: Cedric the Sorcerer, who wants the Amulet so he can use its power to take over the kingdom and overthrow King Roland II.

Thankfully, however, Sofia promised her new stepfather she would never take it off. The one time she broke her promise, a baby griffin stole it, resulting in her being unable to talk to her closest friends-her castle animals-until the Amulet was retrieved.

The Amulet's design may be symbolic in that regard- as well as gemstones telling of the Amulet's beauty, there are chainlinks on the strand, warning of the responsibilty that the bearer must have and their bondage to it when gaining abilities. King Roland II then revealed that, according to tales that his mother told him, that the Amulet is suppose to protect the princess wearing it and that the Amulet chooses its wearer. In Sofia's case, the Amulet must have recognized her perseverance and kind spirit, traits necessary for wearing such a magical item.

Trivia

 * The Amulet of Avalor likely gets its name from a portmanteau of "Avalon" and "Lore" without the e.
 * The Amulet of Avalor protects the wearer from any other magic, as seen in the episode "The Amulet of Avalor", where a baby griffin steals it and Cedric tries to get it by trapping him with a magical cage, but cannot. However, this can be disproven with the fact that Cedric's wand frequently has problems, such as in making rainclouds instead of rose petals, and that the Amulet did not stop Sofia from turning into a lizard after spilling a lizard potion on herself.
 * "The Amulet and the Anthem" is the first episode where the magical amulet curses Sofia. This helps show some truth in Cedric's rumors of its power in the strength of the curse.
 * Roland's mother told him the stories of the Amulet's princess-protecting powers, which helped lead him to accept the Amulet's flash as a mark of Sofia being chosen as the next bearer. This likely means, judging by Roland's account and some portraits, that his mother wore the Amulet before it wound up in the Royal Jewel Room, where it would be transferred to Sofia.
 * The Amulet can only be removed at consent of the bearer-a problem for Cedric, since Sofia will not remove it due to her promise to Roland. Though attempted removal by force has not yet been seen, presuming that the rumors of its great power are true, if Cedric tried to yank it off, he would get some sort of magical blast in return.
 * The Amulet does different things according to the action. When choosing the next bearer, it flashes, and gives off a slight glow. When summoning, it gives off a brief, strong glow. Blessing, the light brightens with sparkles, and when it curses, there are sparkles, but with the light being darker than the Amulet's chief jewel. There may be other actions that it does, but they haven't been seen yet.
 * The Amulet only blesses deeds of pure good, and therefore only curses deeds of pure evil - or rather, it is supposed to. There were emotions behind Sofia's boasting, making the curse slightly harsh, and showing that the Amulet's spirit may be of divine origin, tying to the Evening Star.
 * The Amulet is loosely inspired "looks wise" by the Crown Jewels. The main stone is an amethyst, the stone of royalty, healing and virtue-things that Sofia is connected to in terms of character.
 * The Amulet may have the power of transformation, as The Floating Palace hinted at.
 * Besides rewards tainting pure good, Sofia may not have any new powers due to age-perhaps some are meant for her to gain when she has aged a bit.
 * It can summon Princesses from the past, according to Cinderella, "all princesses that ever lived." The princesses summoned deliver lessons Sofia learns, either by telling of their experiences with the lesson, or of experiences friends of theirs had when learning the lesson.
 * The main stone of the Amulet appears to be an amethyst.