A 'field' of subtle energy can be found in and around any crystal or mineral and the action of placing a thought-form on a mineral can increase its power a hundredfold.

With each crystal or mineral it's the field of mineral energy (non-physical field of subtle energy) that's very specific in strengths and frequencies of vibration.

A thought-form is an intangible, subtle energetic structure that manifests every time we think about anything; we literally create several hundred thousand per day if not more.

We are generally unaware of them because of the current level of our spiritual development.