Depending on the grade spirit veins are usually categorized into three grades namely;
Low grade
middle grade
High grade
Above the high grade is a special type of spirit vein called the dragon vein that is formed from a spirit vein that develops a pseudo spirit in the form of a dragon from the densely rich spirit vein.
Dragon veins are further categorized into three classes;
Lesser dragon vein
Mature dragon vein
Ancestral dragon vein
The ancestral dragon vein is the highest grade of spirit vein recorded that is only seen in Holy lands. It's unknown whether there is a grade above it....