Channelling
The basis of all crystal magic. Channelling energy into yourself comes in many forms
Anyone can use a crystal to power their stove or as fuel for the engines of an airship. Basic crystal use is an essential skill in order to get by in this world, but Channelling the energy of crystals is what makes the difference between the average man and a mage.
Channelling is the base method of utilising Crystal Energy for magic rather than technology. In order to Channel a crystal, you need to take its energy into yourself which grants you the ability to manipulate it for your desired purpose.
This power does not come without risk though, and in the modern day most mages use a staff to aid them in channelling energy. The use of a secondary vessel for the crystal energy mitigates some of the dangers of channelling crystal energy through the body.
An example of channelling is an ability known as a Crescendo. It's a very simple form of channelling, involving a quick intake of crystal energy and a sudden burst outwards, manifesting into a 'blast' or similar effect. This ability is commonly learned by warriors as an offensive ability, but does not qualify one for the title of a mage.
What Makes a Mage?
As stated earlier, not just anyone who uses crystals in day-to-day life can be considered a mage. The distinction comes from an individual's skill in manipulating the energy of a crystal when channelling it through themselves. Refined spells such as telekinesis are considered 'mage skills'.
Backfiring
One of the risks that comes with channelling magic is the chance of the magic backfiring on the user. The effects of crystal energy backfiring can be devastating, the consequences ranging from burns to damage to the nervous system, even resulting in death. It's one of many reasons why most people don't become mages.

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Author's Notes
This article is still in the early stages. Expect to see it updated with diagrams at a later date.