People have always had this fascination with precious stones. We latched on to crystals partly because they have these contradictory physical qualities: They are both dark and transparent. You can see through them, but not really.

That history helps explain the continuing contemporary obsession with crystals and how they are thought to have magical, healing effects and energy.

In the Middle Ages, people also thought that crystals would bring a spiritual presence. They had this hunger to have something physical that embodies faith and spirituality.

We still have that hunger now, and that’s why crystals are so popular. In a way, they fulfill a spiritual need for some of us. Some people go to church, some do yoga, and others collect and meditate with crystals.