Moonbar

Moonbars were rare gemstone unique to the Realms that were found in desert and tropical regions on Toril.

Description
Moonbars were usually found in large crystals, typically 1 ft (30 cm) long by 4 in (10 cm) wide, which were rectangular with rounded corners. Milky white and opaque with a nacreous sheen, moonbars had a naturally smooth surface and, once washed clean, required no further alteration. Cutting was only necessary if the crystals were broken. A typical specimen had a base value of 1,000gp.

Powers
Powdered moonbar was useful as a substitute component in the formulation of necromancy spells. It was also used to make inks, potions, and as a spell component for items that created, controlled, or healed undead creatures, including binding together parts from disparate corpses. Wands that cast "calling" spells (a subschool of conjuration) could be improved by fashioning them using an unbroken moonbar.

Rumors and Legends
The largest known moonbar served as the lid of an unknown king's casket in a barrow on the Trollmoors, and was almost seven feet (two meters) long.