Rudraksha seeds are available in different colors. Even in our old books (pauranik titles), there are descriptions about different colors of rudraksha.
Practically rudraksha colors are following
- Mix colors
- Overlapped color
Location of availbility, environmental conditions classifies the colors to certain extent. Still it is very difficult to classify based on colors. Because of mix colors and overlapped colors, it has been difficult to distinguish rudraksha based on colors.
Scientifically the rudraksha beads are never been classified based on colors. There are no scientific journals describing as such.
After wearing rudraksha as beads/malas for long time, slowly each rudraksha bead brings colors of black or brown. This happens because of sweat effect human body. Also the oil of human body affects the rudraksha color. It is seen that - rudraksha beads without not getting contact with water or body oil, if worn regularly becomes brown-red color down the line.
Pauranic categorisation of rudraksha beads according to rudraksha color has certain purpose. It is told as per the work category of people. People were classified according to their work as Brahmins, Kshatriyas , Vaishyas, Sudras. These category people were instructed to wear rudraksha of differnet colors as below
Brahmins - White rudraksha bead
Kshatriyas - Red rudraksha bead
Vaishyas - Yellow rudraksha bead
Sudras - Black rudraksha bead
Pauranic explainations of wearing rudraksha based on colors has different perspective. And generally this explanation currently does not properly apply to the new system of social thought. But this needs more research and philosophical thinking before commenting more on this.