Message lists also use color coding to identify the status of messages. These are the default colors:
BLUE
Unread message.
RED
Urgent message.
BLACK
Read message.
GREEN
Private message.
FUCHSIA
Message marked for Follow Up.
TEAL
Follow Up completed on the message.
PURPLE
Group message.
You can change the colors used by selecting Preferences from the Tools menu, then selecting Messages-3.