Each Zodiac has a primary color, list what color associates with each Zodiac.

AQUARIUS:
PISCES:
ARIES:
TAURUS:
GEMINI:
CANCER:
LEO:
VIRGO:
LIBRA:
SCORPIO:
SAGITTARIUS:
CAPRICORN:

Aquarius - Blue
Pisces - White
Aries - White
Taurus - Red
Gemini - Red
Cancer - Green
Leo - Red
Virgo - Gold
Libra - Black
Scorpio - Brown
Sagittarius - Gold
Capricorn - Red

That's a different list from any I've ever seen. These are the colors that I know:

AQUARIUS: Turquoise
PISCES: Green
ARIES: Red
TAURUS: Pink
GEMINI: Green
CANCER: Silver
LEO: Gold
VIRGO: Green
LIBRA: Blue
SCORPIO: Maroon
SAGITTARIUS: Purple
CAPRICORN: Brown

P.S. I'm a Sagittarius and for as long as I can remember Purple has always been the primary color.

Here is the source I found
http://www.monamagick.com/resources_colour.html
I haven't a clue really, don't believe in all that mumbo jumbo!

Astrology Insight is where you can find the same info as my answers.

Astrology Online is another good source.