Insight — assayed lots, 1871–1899
Twinned crystal sells; the single cube languishes.
3.4×
+47% vs. plain cubo lots
Iron-cross twinned pyritohedra realised a 3.4× premium per gram over untwinned single cubes across 612 catalogued cabinet specimens.
Fig. 12 — habit yield, brass guilders / g
{hkl} striated faces