- Quartz on Calcite with Anthraxolite (petroleum)
- Middleville, Herkimer County, New York, USA
- Small Cabinet, 5.9 x 4.0 x 1.6 cm
- Ex. James Zigras
This specimen is both fine and subtle, at the same time, front and back...For the front, we have one description: Emplaced aesthetically on rhombohedral crystals of translucent, ivory colored calcite, to 2.7 cm across, is a single doubly terminated, glassy and gemmy quartz crystal measuring 3.7 cm across. The nearly colorless quartz crystal is partially included by anthraxolite, a noncrystallized bitumen-group organic carbon mineral (basically, frozen petroleum inclusions). A matrix specimen of a Herkimer Quartz, ON CRYSTALLIZED MATRIX, and WITHOUT REPAIR, is 1 in 1000! So, already this is a phenomenal specimen, and rare in its peer group. The back side, however, is maybe even more interesting: The back side features a pseudo-crystallized anthraxolite (bitumen) "crystal" that looks like a flat square with rounded corners. It is incredibly reflective, like black jet glass, and tucked into crevasses of the calcite and the quartz, anchored firmly in place. It seems to be complete, and without damage. It actually looks like nothing so much as a polished wad of black glue, attached to the bottom of the specimen - and this may indeed be the function it severs (as a fortunate accident), lending stability to a thin calcite plate that otherwise would have broken away from the quartz atop, in the pocket or during mining. I really find this specimen interesting, and it is certainly unique in my experience. I first went collecting at the Herkimer quarries as a teenager in the late 1980s and have never seen anything quite like this. Ex James Zigras collection.