INAA of agate sources and artifacts from the Indus, Helmand, and Thailand Regions
"Geologically speaking," write the authors, "agate is not a particularly uncommon rock . . .. However, good agate – i.e, that which ancient lapidaries would have found suitable for beadmaking – is not widely available. Nodules of the size and quality required to make Harappan-style long-barrel carnelian beads are, in fact, extremely rare" (p. 177).