Sometimes Quartz that has broken from its place of formation, through tectonic movement or extreme temperature changes, can ‘heal’ itself in the right conditions. Self healing or Re-healing is when the Quartz continues forming over the fractured section of the crystal to form new faces and terminations. Here is a Quartz crystal that has begun to heal, you can see the beginnings of the geometric crystal faces taking shape.
Sometimes a piece that has separated heals so well that you can’t tell where it separated at all, this is referred to as a “floater,” and many are highly prized collector’s pieces like this Smoky Quartz, which has formed many stepped, triangular terminations over its fracture.