Tchazar

Tchazar was the Realms name for aragonite which occurred in long, prism-shaped crystals that were straw-yellow and very fragile.

Description
A lapidarist of great skill was required to cut faceted gems from this semi-precious stone. Cabochon-cut tchazar was much less valuable (treated as an ornamental stone). A typical specimen had a base value of 50 gp.

Powers
This gemstone was important to those who feared magical scrying because tchazar interfered with scrying devices and spells, rendering anything within 2 ft (60 cm) of a tchazar stone blurry and indistinguishable. The effect was the same regardless of how the tchazar was cut (cabochon, facted, or natural crystal) so it was used to adorn many personal items and locations where privacy was of utmost importance. This magical smoke screen effect was lost if the tchazar stone was shattered.

Computer games

 * Icewind Dale