Is it possible to use "editor-color-palette" instead of the iris color picker?
Then define the palette:
add_theme_support( 'disable-custom-colors' );
add_theme_support( 'editor-color-palette', array(
array(
'name' => __( 'Light gray', 'genesis-sample' ),
'slug' => 'light-gray',
'color' => '#f5f5f5',
),
array(
'name' => __( 'Medium gray', 'genesis-sample' ),
'slug' => 'medium-gray',
'color' => '#999',
),
array(
'name' => __( 'Dark gray', 'genesis-sample' ),
'slug' => 'dark-gray',
'color' => '#333',
),
) );