These are important because you need certain candle colors for specific rituals.
Orange: Attraction, stimulation, control, personal strength, authority, power, encouragement, adaptability, luck and sudden changes.
Yellow : Creativity, intelligence, confidence, movement and energy. Connects to clairvoyance, divination, wisdom, learning, imagination and inspiration. Power of concentration and communication.
White: Symbolizes peace, purity, innocence and power of a higher nature. Promotes peace, tranquillity, purification, truth spirituality and sincerity.
Gold: Promotes understanding and attracts the powers of cosmic influences, intuition, persuasion, charm and confidence.
Red: Invigorating color of energy and life. Connected to blood, birth and death, and sex. Connects with love, passion, fertility, physical energy and strength.
Pink: Positive symbol of emotional love, nurturing relationships and romance, promotes spiritual awakening, healing of the spirit, femininity, friendships, honor and morality.
Purple: Highly spiritual and traditionally connected to mysticism, inspiration, wisdom, idealism, purification, success, peace and power. Aids in meditation, sensitivity and higher psychic talents. Connecting to idealism, ambition, power, success and household protection.
Magenta: Highly vibrational frequency that tend to work fast. High levels of power of spiritual healing are required, such as quick changes, exorcism or spiritual healing.
Indigo: Used to cleanse the spirit and remove fear. A vitalizing color of inertia. Used to counteract negative energy.
Brown: Earthy, balance color used to attract money and financial success. Aids in emotional stability and balance, eliminates indecisiveness, improves powers of concentration, study, intuitions and telepathy.
Blue: Soothing and relaxing color, Primary spiritual color, used to obtain wisdom, tranquillity and harmony, peace, inner light and truth. Connects to inspiration, occult power, protection, understanding, good health, patience and loyalty.
Green: Nature, fertility and rejuvenation, works involving financial issues and money, aids good fortune, prosperity, luck, ambition and success.
Silver/Gray: Removes negative energy or influences and encourages stability.
Black: Opens up the deeper levels of the unconscious. Good for banishing evil or negativity. Connects to self control, quiet power, and resilience, absorbs negativity and destroys it.
Information from RedDeer's Wicca 101 and To ride a Silver Broomstick by Silver RavenWolf