As was stated earlier, there is another way to do this. Creating crystals from how they fall out of a solution as they evaporate is playing around with its phase state, but the underlying molecular form of the compound remains unchanged. Compounds can be created from molecular bonds. Molecular bonds are formed from covalent bonds where electrons are shared. How those electrons are shared depends heavily on quantum numbers that describe properties of the orbitals of an electron. By manipulating probabilities and statistical properties of the reaction, the underlying formula of the resulting compound can be forced into a state that conforms to the enchantment. As was stated, this route is a little bit more complex than creating a magical crystal from an evaporating solution. More information on this can be found at: Electron Structure and Periodic Properties of Elements
Since the crystal was formed and created by magic, this implies that the magic that caused it to be is bounded up in its continued existence. If the structure of the crystal is not compromised, the structure of the enchantment is not compromised. Due to shifting statistical ensembles, the enthalpy of the crystal is also changed – in other words, the enchantment creates a tangible form of the energy you can hold in your hands. By changing the enthalpy, the magic allowed you to physically store more energy in a coalesced crystal than would have been possible. This firmly anchors the magic into the physical realm such that it is not as ephemeral since what caused it to exist and continue to exist is an innate property.