A magical ice crystal
Attunement
A small shard of deep blue ice inside a thick tube of glass, attached to an iron chain. Unless covered with an insulating material, The shard emits an aura of extreme cold in a 5-foot radius around itself.
The shard must be held in the hand for 1 hour while blue tendrils of ice travel up your arm and spread over your body. At the end of the duration you must make a DC 20 Constitution saving throw.
On a failed save the shard releases a burst of ice crystals causing you to take 4d6 cold damage. In addition, you are frozen in ice and become petrified for 1 hour. If you fail to attune you cannot attempt to do so again until you have finished a long rest. On a successful save you attune to the shard. While attuned to the shard you gain the following features.
Attuning to the Winter Shard grants you knowledge of Winter spells, allowing you to sculpt ice and chill your foes. The shard must be held in the hand to cast these spells.