Kathryn Harwig (now retired) was a phenomenal person to know. Catherine actually began her palm reading journey with a book Kathryn wrote called Palm Visions.
In this book, one of the marks of psychic ability she identifies is the Psychic Cross.
Keep in mind, having this mark does not mean you are psychic – but rather, you have a great interest in psychic or mystical studies. It is this open mindedness that allows you to release fear of the unknown, bias, etc. so that your natural abilities can come into awareness.