The Bluestones, which are found primarily in the Bluestone Hills, but also in a few other remote hilly areas of the world of Gemnos, are magical gemstones with different properties.
Over the years, sages have catalogued at least three different types of Bluestones. There are rumored to be at least two more, the Soul Bluestone and the Starflare Bluestone, but there is not enough information on those.
Clear Bluestones enable a spellcaster to draw on it's energies and recall a spell he has previously cast the same day.
Jagged Bluestones have one purpose, namely to empower rituals, especially conjurations and divinations.
Essence Bluestones can be used to store spells inside, to be activated at a later time.
As a rule of thumb, the bigger the Bluestone, the more powerful it is.