Some articles on dragonshards, dragonshard:

World Of Eberron - Dragonshards
... Dragonshards are rock or crystal fragments originating from the three legendary dragons of Eberron's creation myth ... of Eberron's world, Siberys, Eberron and Khyber, each produce a distinct form of dragonshard, with a unique appearance and distinct magic affinity ... Dragonshards are among Eberron's most important resources ...