Editing SpheresoftheAether (section)

===Sphere===
The sphere is the core skill of magic. Each Sphere is an IQ/VH or DX/VH Skill. This represents knowledge of the Sphere and the workings of its magic. A Domain's skill can not be higher than the Sphere skill.
Additionally, a character's skill level in their Sphere, plus their level of magery is the number of charms and conditional spells they can have.
Domain
The Domain skills are the skills that are used for actually casting magic. Each Domain skill is an IQ H or VH skill. They do not have defaults.
A Domain skill's level cannot exceed the lower of Sphere skill level, or Magery + 12.
This of course, doesn't apply to modified skills from items, such as the physical Sphere itself.
Spell
Mages may opt to focus on specific spells to improve their skill with them. These are taken as Average difficulty techniques based on the relevant Domain skill.

 For the purpose of these rules, a ritual is defined by the following things:
The specific spell effect(s) (TH:RPM pp.15-16); e.g., “Lesser Strengthen Body and Lesser Destroy Chance.”
What those spell effects do. This is somewhat subjective, but there’s a clear difference between (e.g.) “Lesser Sense Mind to send my thoughts” and “Lesser Sense Mind to locate the nearest sapient being with IQ 5 or less.”
Which of the following modifiers (TH:RPM pp. 16-18) are used, though you don’t have to list the specific value – it can be changed “on the fly” without issue: Area of Effect, Healing, Meta-Magic, or Speed.
Which of the following modifiers are used and their specific effect – this cannot be changed without being considered a new ritual:
Afflictions, Altered Traits (you must list the traits, but if they’re leveled, you can vary how many levels you add), Bestows a Bonus (you must list the rolls affected, but can vary the strength of the modifier), Bestows a Penalty (as for Bestows a Bonus), or Damage (you must list what type of damage and any enhancements, but can vary the amount).
Don’t bother listing Duration, Extra Energy, Range, or Subject Weight – as these can be varied freely with any spell.

IQ/H, what does that mean?
Every Skill and technique in GURPS has a difficulty. This ranges from Easy to Very Hard
If you see IQ/H or DX/A or something like that, it tells you the attribute the skill is based on, and the difficulty.
See Basic Set: Characters page 171 for more details, or GURPS Lite page 13