Dark Shard Dice

This dice originates from the realm of Moander.
While it is on your person, you gain the
following benefits:
•You can use the dice as a spellcasting focus for
your warlock spells.
•Once per long rest you can try to cast a cantrip
you don't know on the warlock spell list with a
DC 10 Arcana check. If the check fails, so does
the spell, and the action used to cast the spell
is wasted.