My ex-wife was a crystal yakkey-takkey specialist. She had a crystal almost every know ailment or situation. We had crystals under our bed. Was supposed to bring harmony into our lives. Every plug point or electrical appliance had a crystal attached to it or near it. This cancelled out the negative energies produced by them.
I even had a special crystal I was supposed to,carry in my pocket to,protect me from harm. It wore a hole in my pocket, that's all.
It's a heap of fuckwittery but there are so many people out there who believe in the magical properties these magic crystals bring.
And, it's big business.