However, I don't display all crystals at a talk or fairs. Certain crystals can be very potent and 'serious' so I keep these for training purposes only; for those who are on a conscious path of development and can handle the energy.
I recently ran a retreat at a spiritual centre at which I also gave a talk to the wider community. During the talk I had a table of crystals for attendees to look at, sense, and buy from, should they wish. Normally the table is right by me, so I have some awareness of what's happening energetically, in case something feels too much for someone. Because of the layout of this room though, the table was on the far wall. I felt this community were more spiritually and energetically aware so I thought at the time this was okay.
Before the talk began a crowd eagerly gathered round the table of crystals, and again, once the talk was over, a big crowd surged around the table. They clearly loved their crystals, which was wonderful to see.
It's really important to stress that the energy of crystals is 'real' and just because we may not 'see' with our eyes how they are affecting us (instead we may feel it, or just 'know'), does not mean that they are not having a huge impact. This is why a serious professional long-term training with crystals (of a minimum of two years) is so important before working with them on others. To place a crystal within the energy field of another human being carries an enormous responsibility. A proper training helps to ensure that you will be coming from at the very least, a place of least harm when you do this, and you never know, you could potentially even truly help that person proceed on their life path!