Chardalyn

Chardalyn, also known as Black Ice or Dark Ice is a black crystalline material with a dark blue sheen that is as strong as metal, though considerable easier to work with than steel. Cold to the touch, you have discovered that may of these deposits are suffused with demonic magic. Prolonged contact with desecrated chardalyn that has become suffused with demonic magic can warp a creature’s mind, causing madness that usually fades away once the contact is broken.

In Session 11: the party learned that Amelia seems to be immune to the effects of desecrated chardalyn.

Chardalyn is cold to the touch and readily accepts magical enchantment, making it an ideal substance for wands, staffs, and other magic items. A chardalyn object suffused with the magic of the Upper Planes is considered a consecrated object, while a chardalyn object suffused with the magic of the Lower Planes is considered a desecrated object; both can be identified as such using a detect evil and good spell or similar magic.
Desecrated Chardalyn Each day at dawn, roll a d6 for each chardalyn amulet in a character’s possession. On a roll of 1, the character must succeed on a DC 10 Charisma saving throw or become lawful evil. A lawful evil character craves power and tries to exert control over others, by being either cruel or manipulative. The alignment change can be undone by any magic that ends a curse, but after nine days, it can be reversed only by a wish spell or divine intervention.
The chardalyn amulets worn by the Knights of the Black Sword in Caer-Dineval (Session 6: Knights of the Black Sword) have been corrupted by the influence of an ancient evil devil. A detect evil and good spell or similar magic reveals that the amulets are desecrated objects.

Raw Chardalyn

Chardalyn Amulet