Depending on your blueprint some people may like to have close contact with their crystal by touching or holding while others may like to place it near by.
Also depending on circumstances one may prefer to hold it, or simply leave it within the space. For intances, when you are using its healing properties to heal a certain area of your body, you may like to place it right at the identified area. Reason: solid items has vibration, the closer the crystal is placed at the area, the transfer rate of the crystal vibration/frequency is fast.
Another instance is when you need to use the healing properties or do a download of codes to crystals that you have placed at home or remotely. All you need to do is to set intention to link to your selected crystal by simply imagine or recall its appearance. Simple as that.