http://www.crystalvaults.com/pages/quartz_crystals_explained.php#p
(note: Under "portal" it redirects you to "timeline to past/timeline to future)
Time Line to the Future Often incorrectly called Activation Right. Time Line crystals describe a special kind of quartz crystal that contains a seventh face that is just below the six main faces of the termination. This special face is in the shape of a parallelogram, which is similar to a rectangle turned at an angle leaning right.
Time Line to the Past Often incorrectly called Activation Left. Time Line crystals describe a special kind of quartz crystal that contains a seventh face that is just below the six main faces of the termination. This special face is in the shape of a parallelogram, which is similar to a rectangle turned at an angle leaning left. Also known as Ancestral Time Line.