According to Professor Shirley Harrison, Mystical Artifacts have different levels of strength or power. With this difference, the Association of the Harmonious Arcane Paths created a standard ranking system for these artifacts. They were ranked according to their contained powers, effects, limitations, and usage requirement.
There were a total of six ranks and each of them was still divided by three grades. They can still be low-grade, mid-grade, or high-grade.
The lowest rank was called Regular. They are the ones similar to Spirit Pearls that can slightly boost your intelligence. Almost all Regular rank items don't have side effects because their effects are too negligible in most cases.
Perhaps, only some poorly made Regular Rank mystical items can have a bit of side effects on them.
