The planets involved (as well as their sign placement) will determine the particular expression, but generally speaking a quintile aspect is a reservoir of creative potential simply waiting to be drawn from via the two planets in aspect. With Mars quintile Uranus, one expression that comes to mind would be aptitude for very creative solutions to humanitarian issues, perhaps serving as a vocal and persuasive proponent for a cause or ideal in the face of adversity. A more mundane interpretation could be an innate talent for finding creative solutions to challenges the person is faced with, particularly in the areas of life shown by the houses the two are placed in. Sign and house placements will reveal more of the nature of the aspect, and of course factoring in the rest of the chart.
I've asked a billion times what a quintile aspects means and I'm still not capable to understand it. It's too theoretical! I don't feel how it works.
I have a Venus Taurus (10th) quintile Jupiter Pisces (7th).
I know that this is an important quintile because if it represents creativity, than it's on the right place being connected to two benefics, in angular position, in domicile!
But what is it????
Full Moon Libra,
I found this in a book I have, I don't know if it's the type of info you're looking for, but hope it helps:
The quintile is an aspect of 72 degrees.
"The quintile bestows a naturally well developed capacity which is merely waiting to be brought to the surface. It is usually thought of as an intellectual aspect, being described as Mercurial in its action.
There is something very creative about it and often something occult or hidden. Not all authors agree about the way it acts. John Addey, for instance, gives it the meaning of purposefulness and points out that we often find this aspect in people of positions of power, and also in people who are striving for power."
I'm going to add here it is a minor aspect and was not much used, I am finding it increasingly used however in chart interpretation.