Green color with dark purple inside.  Here are some better Pics.

http://i255.photobucket.com/albums/hh156/ggolbs/seashell021.jpg

http://i255.photobucket.com/albums/hh156/ggolbs/seashell026.jpg

It's been suggested that the green color is from algae dyeing the shell. upon close inspection I do not feel this is the case. I haven't seen a pic of a jewel box with purple on the inside like this either. please let me know what you think.