The Jasper's Light was an item of good magic, shown in the episode "The Tale of Badge".
They are a series of magical ruby amulets handed from generation to generation in the Setterwind family bloodline, passed down from grandmother
to granddaughter on the granddaughter's sixteenth birthday.
This tradition has gone on for six centuries, and when the granddaughter receives the amulet, she in fact becomes the new mistress of the Setterwind family magic, but is also required to accept the responsibility that comes along with the magic: guarding the badger-like goblin, Badge, who is a manifestation of the evil part of the Setterwind magic.
If Badge is to escape, The Setterwind is to hold her amulet and say the proper magic spell to banish Badge back into the containment crystal.
Spell to Banish Badge
By Darkest Night,
I play the Song;
To hold the Beast
In Moments Long.
I call upon the Jasper's Light
To bind the Goblin
In Setterwind Might.
As revealed by Gwen's confrontation with Badge, only a Setterwind witch who is thoroughly skilled and experienced in her magic is able to utilise this spell to banish Badge. If not, she will have to rely on The Setterwind Magic Flute to banish him.