In Flammeus, Talla likens her mind to an emberjar. An emberjar is a small pierced clay jar which is used to transport live coals with which to start new fires.
When Talla feels angry, she feels as though the live coal in her mind is glowing brightly, stoked by the actions of others.
Part of the dedication in Flammeus reads
"May the Emberjar of your mind
be sparked by love,
fed with curiosity
and shared with compassion."
This series of books is called The Emberjar....