Aquamarine of Spell Extending

This blue stone mounted in the center of a gold and silver hourglass. Once per day the owner can use the Extended Spell metamagic (When you cast a spell that has a duration of 1 minute or longer, you can double its duration to a maximum duration of 24 hours) on any spell of 6th level or lower. The spell being extended uses its normal spell slot and the item must be held in hand while the spell is cast to get this effect