The definition of a crystal is "a piece of a homogeneous solid substance having a natural geometrically regular form with symmetrically arranged plane faces".
Hence in a crystal, each of these geometric atomic shapes stacks together in a geometrically symmetrical lattice structure.
Thus, crystals represent the most perfect natural representation of sacred geometry in physical form. Nature, can indeed form straight lines!
As each crystal has a specific crystalline structure they each form a unique specific harmonic frequency with a unique dominant oscillatory resonance. The larger and more perfect the crystal structure, the higher the amplitude (or power) of the energetic wave.
The coherent, resonant, high amplitude wave forms produced by crystals are perfect for entraining frequencies within the human body which can bring the body back into a state of healing on multiple levels ~ physically, mentally, emotionally, and spiritually.