Using homebrew and zsh

homebrew coreutils [brew install coreutils] installs a dircolors equivalent called gdircolors

In the file .zshrc (at the end in my case), I put two lines 

  eval $(gdircolors ~/.dircolors)
  export LS_COLORS

and that did the trick. I seem to be able to use any of the colours 0-255 (but they don't all give the colours expected).

Code in ~/.dircolors :

The file begins with a list of TERM types to which this applies (my terminal is xterm-256color which seems to be the default in MacOS Terminal.app since MacOS 10.7). For the colors there's a list of items of the form 

 DIR 05;33   (not a recommended combination!!)

or 

 .zip 01;105

see the blog page on configuring-ls_colors

To list all colours (in zsh, needs modifying for other shells): 

 for i in {1..256}; do print -P "%F\{$i\}Color : $i"; done;

Note that these colours all seem to work in the prompt (defining PS1 etc in .zshrc) but not in ls. I haven't yet figured out which ones work - or how the different colours respond.

References