"I was under the impression that a Bi-quintile was twice as strong as a quintile???? I know its minor but I have that Mercury in the 8th. I gotta know everything on a deeper level."

Oh I didn' think so, but as I say, I tend not to pay too much attention to the quintiles and biquintiles, so maybe you're right.
I have Mercury in the 8H too so I understand the need to delve deeper. I'd suggest looking through the other aspects in your chart more though or getting a book on quintiles/biquintiles, I think Michele recommended one!
If you understand more about the quintiles/biquintiles you probably won't need a 'cookbook' type interpretation!

I don't think biquintile is weaker than a quintile

just like binovile,quadranovile aren't necessarily weaker than novile
(trinovile is a narrow orbed trine....3/9 = 1/3)
nor biseptile,triseptile more weaker than a septile
nor biundecile,triundecile,quadraundecile,quinqueundecile more weaker than undecile

they are are of the same harmonics
they are appear as conjunctions in the corresponding harmonic chart


here are some interpretations for the quintile and biquintile

www.cafeastrology.com/natal/q...ile.html


From Robert Hand's Horoscope Symbols:
5TH HARMONICS
It is said to be a quality similar to Pluto,with overtones of Venus and Mars: some kind of concrete creation or destruction is effected. Intellectual functions (not excluding emotion) and all especially human matters. Transformational change. The ability to express creative inspiration (due to other factors) in concrete creations.

from clairvision:
Astrological aspects – biquintiles
Biquintiles in Clairvision Virtual Astrologer

Note: to quickly judge the biquintiles in a chart, Clairvision Virtual Astrologer has a drawing preset called 'Biquintiles Only'.

The biquintile is an aspect which is usually regarded as very minor. At the Clairvision School, however, we have found it to be extremely powerful, at least in certain charts.

There are some symbolic reasons for this. What is a quintile? An aspect which measures a fifth of a circle, that is, 72 degrees. What is a biquintile? Twice a quintile, that is, 144 degrees – the measure of a pentagram.

If you draw a pentagram, or five branched star, within a circle, you can easily see that between each spike, there is a quintile (a fifth of a circle), and that each line of the pentagram delineates a biquintile, or two fifths of the circle.

The pentagram is perhaps the most magic of all figures of sacred geometry. It symbolizes occult power, the mastery of esoteric principles and of astral forces. It has sometimes been used by black magicians (who use it 'upside down') but there is nothing intrinsically evil in it. The pentagram is sheer power, and can be used for either pure or evil purposes.

This is exactly the significance that we have attributed to the biquintile – deep occult power. For instance, in the 'Teachers' database, look at Uri Geller's very tight Mars-Saturn biquintile (12').

It has appeared to us that biquintile spikes are particularly powerful. In terms of sacred geometry, one can easily see a reason for this. When two biquintiles are organized in a spike, they form the beginning of a full pentagram.
astrology.clairvision.org/stati...s.html

The Biquintile, as the name implies, is a 144 degree aspect showing a unique interactive situation, where one gift interacts with another gift, creatively and/or regeneratively. It is an interactive unique form of self-expression that often involves other people and their unique gifts, whether they align harmoniously with yours or not.
www.aquariuspapers.com/astrol...ec.html


Biquintile: (144 degrees)—Planets separate by two-fifths of the zodiac indicate the quality of inborn talents.
source: Mapping Your Birthchart, Stephanie Jean Clement, Ph.D. (Llewellyn Publications)
www.llewellyn.com/encyclope...=astroup25


Dane Rudyar

HASE 15 - The Waxing BiQuintile

KEYNOTE: A capacity for self-sufficiency, assuring the fulfillment of unfolding qualities in the face of enduring forces of disintegration.

SCENARIO: With the momentum of the trioctile behind it, the sweep of the cycle now rushes toward the decisive opposition and its "parting of the ways." If new qualities of being have been allowed to mature and operate at a higher level of the cyclic process, here they become empowered to survive the pull of rebounding pastward forces guarding the way to the waning hemisphere of the cycle.
If a definite effort was initiated during the previous phase to finally break the bondage of the past, this phase brings the means to do so. If development has been mostly futureward, rising individualism may introduce the possibility of a new type of failure. Yet at the truly human and existential level, new qualities of being require individuals to embody them if they are to be effective and fully actualized.

DYNAMIC: The development of mental faculties and imagination witnessed in previous phases now provide a capacity for formulating creative solutions to problems met along the culminating steps toward fulfillment. The areas and activities symbolized by the planetary pair feature the development of the inner resources and capacities required for actualization.
www.khaldea.com/eon/eon15.shtml


PHASE 23 - The Waning BiQuintile

KEYNOTE: A capacity and determination to plumb the depths of existence in search of significant experiences and underlying forces.

SCENARIO: Exposure to the objective world, and the expansion of social horizons and the new possibilities it brings, leads to a need to explore and understand the movement of forces operating beneath the surface of social and personal life. Self-reliance and the development of individual capacities are featured. But whereas the waxing biquintile saw the unfoldment of innate or organic faculties and capacities, the waning biquintile calls for the willful development of unique, individual capacities and the rise of technological knowledge and skills capable of extending innate faculties and capacities.
When a pastward, separative attitude reigns, this phase carries the symbol of the individual attempting to stand alone against the greater whole, and, in another sense, the destructive, perverted use of knowledge and technology. When a mostly futureward and integrated attitude prevails, the individual dedicated to the actualization of the new qualities of being unfolding through the cycle now assumes the role of a creative participant within a social or universal order. But the force of individualism may still overtake the aspirant who takes too much pride in such a role and confuses his will with that of the cosmos.

DYNAMIC: The flood of possibilities shown in the previous phases now required a reality check, separating the fanciful and unattainable from what is realistic, possible, and needed within the context of the current cycle. What is needed now isn't more possibilities but a widening scope of meaning and understanding. As the universal principle of differentiation and the force of individuality ebbs, it becomes even more internalized in the individual who now a creative power in the cosmos, for better and for worse.
www.khaldea.com/eon/eon23.shtml

SABIAN ASPECT ORBS by Robert Blaschke

all waxing biquintiles, no matter what their orb,represent inner self reliance and at willingness to cross barren spaces in pursuit of a goal or ideal. As the waxing biquintile falls within the gibbous phase, it reveals the relationship between the two planets in aspect involves a search for illumination and self-sufficiency.

all waning biquintiles,no matter what the orb,represent childhood in which the assumption of parental responsibility diminishes the carefree nature of youth and accelerates development of character which molds the individual to participate as part of a team. As the waning quintile falls within the third-quarter phase and represents internal resistance toward self-expression, the astrologer can presume that clients with these aspects need extra encouragement to feel free to leave behind demanding careers or heavy responsibilities that impede true expression of their artistic or creative abilities.


5TH HARMONIC ASPECT SERIES - QUINTILES POTENTIAL TALENTS AND ABILITIES Quintiles [1/5 or 72 degrees]; and Biquintiles [2/5 or 144 degrees] do not function at the obvious level of visible personality traits and behaviour patterns, but they are among the most overt, influential and powerful of the Potential Aspects.

Known as the 5th Harmonic Aspects, they have a lot to say about the potential talents and abilities indicated by the planets they link.

The Quintile Aspects are generally more intellectual than the Deciles or 10th Harmonic Aspects which they otherwise resemble very closely. If any Quintiles or Biquintiles in your chart are strong, the potential talents will probably surface readily. However, if they are weak, then it will take deliberate, conscious work to bring them to fruition. Planets linked by quintiles say a lot about the stylised patterns of behaviour you might adopt in life. When powerfully strong, they can even be expressed as compulsive behaviours and attitudes. However, experience suggests the principal effects of quintiles relate to talents and abilities and that it is only when they are handled badly that they lead to compulsive or obsessive behaviour patterns. The Biquintile is believed to be a little harder to handle than the Quintile.
cura.free.fr/exegesis/exegesis0026.html

Quintiles are measured from plus or minus seventy-two degrees. Bi- quintiles are measured from plus or minus one hundred and forty four degrees which is one or two fifths of a circle. When planets are quintile or bi-quintile this is an indication of uncommon creative energy and talent. They are trend-setters and need an audience. The energy here is specialized and purposely striving toward power. Quintile and bi-quintile energy can be romantic, playful and demonstrative. The quintile family of aspects can indicate science, math and engineering. There's a need to make things happen. Cosmic will seems to be at play here, so if creative things aren't happening, then look for destruction. Quintiles and bi-quintiles bring a certain dignity, clarity, pride and unusual sexual energy. A quintile resonates with the Sun, Fixed, Fire and Leo energy.
www.adze.com/Classroom/aspects.html


I have Mercury in Scorpio in 3rd biquintile Eris in Aries R in 8th - '06

I also have Sun in Scorpio in 3rd biquintile Midheaven in Gemini - '05