Side view of specimen shown in photo SSX27a. Note the flattened grains of willemite and franklinite in the ore, which collectively define a gneissic foliation dipping to the right. The fault upon which the sussexite was deposited cuts this foliation at a high angle. Note here that each splinter and fiber of sussexite is attached to the ore on its right end and grew toward the left, within a progressively dilating void, as faulting gradually took place. Such material is “gold” to geologists because the fibers provide a detailed record of the movement of one fault block relative to the other.
Identifier: SSX27b Locality: Franklin mine, Franklin Specimen size: 9 x 6.5 x 4.5 cm Photo credit: Earl R. Verbeek