WordPress Color Picker customizing

Hi,
please is there any way to customize the WordPress 3.8 color picker (on the custom field types) to use only colors i will define?

I need to have only 6 colors for a client, but they do not want to have all those colors, apart from 6 gradient colors.

Will be greatful for any help… I have been trying to do it for several days, but no positive solution:(

Thank you