Peridot

Peridot (ペリドット Peridotto) is a female Papillon Jewelpet who represents Positiveness or Dream Fulfillment.

Personality
According to the official website, Peridot is depicted as a spiritual being who loves to play with butterflies.

In the anime, Peridot's personality varies within each series, though in most of her incarnations she is depicted as an American. Jewelpet Twinkle☆ had that aspect of her character removed, only to be restored in the airing of Jewelpet Sunshine (and the following series after that).

Jewelpet Magical Change gave an interesting twist to the idea: Everyone around her assumes she must be from an English-speaking country because she mixes English words and phrases into her casual speech, but that's just an affectation, and she isn't actually fluent in English.

In most series, she's usually lively and full of energy, and also very nice and kind to others around her.