Laën, an unbreakable rock with glass-like texture, was usually found in volcanic areas and seen by most as a relic of the great wars between the Valar and Morgoth. The Tower of Orthanc in Isengard was made of Laën as well as the first Ring of Minas Tirith. Most common was Black Laën, although other colors or even clear variants were known to exist. Laën carving was a very rare craft, only known to small circles.
- MERP Rulebook 2nd Edition
- The Gems of Middle-earth, online essay by William E Wilson