Information - Deeper
Here is some miscellany on Emeralda, which you may or may not find particularly interesting.
Name Meanings
Emeralda is easy enough to decipher; it refers to the gemstone "emerald", as her hair color is green.
Kasim is an African name meaning "Controller of Anger". It can also be Arabic for "Divided".
Scent
In Perfect Works, the creators gave most of the characters a "scent". Emeralda's is In Love Again by Yves Saint Laurent. According to a translation from Guardian Angels, the creators were going for "...a marvelous creation, supplemented by a strong, kind soul. In Love Again symbolizes Emeralda's renewed love for her father who is now named Fei..."
The first part is right on the mark (though how they got it from a scent is beyond me), but I guess they were going for a meaning of love closer to filial love; the Japanese, unlike American English, has more than one word for "love". Perhaps they meant the innate love a daughter has for a father.
Nanotechnology
I'm not smart, so if you want to learn more about nanotechnology check out either Guardian Angels or Wikipedia.
Crescens
According to Bible Gateway.org's NASB:
Why they chose such an obscure reference that doens't fit is beyond me. As a stretch, it could be said that Emeralda abandoned Krelian, but she didn't; Krelian had no intention of keeping her.
As for why Crescens isn't named after a constellation like a number of other gears, it's because it's technically of the Vierge class. Crescens is more than likely another type of name for it.
The actual etymology behind "Crescens" would be that it shares the same root as the English word "increasing" (much like how a crescent moon is a moon that increases in visual size due to the lunar cycle).
Vierge
Like most of the gears, Vierge is named after a constellation; in other words, Vierge is another word for Virgo. It could also be a reference to the Blessed Virgin, Mary.