Jet is fossilised wood, polished to a deep black, and was worn for mourning in Victorian times. Dream tradition reads it as grief held with dignity and protection during a dark season.
Where in your waking life have you met something like this lately?
My Cosmic Code has a private dream journal. Write a dream down and the app picks out the symbols in it, shows what dream books say about them and, over time, which words recur across your entries. The journal is stored on your device only.