Source: Lost Mine of Phandelver and Phandelver and Below: The Shattered Obelisk

Staff, Rare (Requires Attunement by a Bard, Sorcerer, Warlock, or Wizard)

This slender, hollow staff is made of glass yet is as strong as oak. It weighs 3 pounds. While holding the staff, you have a +1 bonus to your Armor Class.

Spells. The staff has 10 charges. While holding it, you can expend the requisite number of charges to cast one of the following spells from the staff: mage armor (1 charge) or shield (2 charges).

The staff regains 1d6 + 4 expended charges each day at dawn. If you expend the staff's last charge, roll a d20. On a 1, the staff shatters and is destroyed.