Socrates in Phaedo, when describing 'the real earth' said that the colours which we know are only limited samples, like the paints which artist use; but there the whole earth is made up of such colours, and others far brighter and purer still.
The Jewish historian in the first century AD-associated white with earth, red with fire, purple with water, and yellow with air. Lord Home Page Centuries later Leonardo da Vinci settled his colours preferences as "white for the light so it can be seen without colour; yellow for the earth; green for water; blue for air like the sky; red for fire and excitement; and black for darkness and occultism.
Some of these colours are still used in astrological traditions and tend to be grouped as follows:
Sun - gold, bright yellow. Its astrological sign is Leo. Being assigned red, gold and sometimes yellow-green.
Mercury - another volatile ruler of two signs, usually associated with yellow or orange. Gemini and Virgo share these colours.
Jupiter - the royal planet - use purple sometimes violet or russet reds, shared with Sagittarius.
Saturn - olive green and grey, sometimes dark greens and black. Assigned to Capricorn.
Uranus - in Aquarius - always light colours. Use favour electric blue, pale greens or citrine.
Neptune - mystically happy in Pisces, use several colours such as dark blue, indigo, greys, green in a film nature.
Pluto - still a bit undecided with pale green, yellow and navy blue suggested. It will require to use your own feelings as a guide to this one.
Earth - our lovely planet is often assigned lavender-blue or white.
Don't forget to subscribe for updates!
See also The-use-of-colour-to-heal
Resource: The healing power of colour, Betty Wood.