Above:
The Passaic Pit during the 2008 Diggg at Sterling Hill. At
left is a big boulder made of "salmon calcite". This is always popular
with collectors. The calcite is pink in daylight but also fluoresces
red-orange in short-wave UV. With some luck it's possible to find
spots of white-fluorescing barite in this material.
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The
2008 Diggg was a success, thanks to Jeff Winkler, Eric Weis, DVESS, the
SHMM, and everybody else who worked to make it so great. Special
thanks goes to the Haucks, without whom there wouldn't even be a
Sterling Hill as we know it today.
It was really good to see everybody at the dig-- quite a few of the usual crowd, plus many new faces. This is what it's all about! Mineral collecting is one of the finest hobbies out there, but it wouldn't be the same without the great people. It would have been a nice idea to snap some pictures at the banquet, an annual event that has its own cast of characters (many of whom are long-time field collectors who've graduated to the silver pick). |
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Below: Within the Sterling Hill complex are some interesting sub-regions of mineralization. The photograph below shows some altered scapolite from the Noble Pit. This material sometimes has cavities that contain micro crystals: there can be aragonite, calcite, cerussite, fluorapatite, goethite, malachite, azurite, or any of several other minerals. 
A potato-sized chunk can keep a person busy for hours. Trying to identify every mineral species in the rock can take much longer! Going through your collected material with a microscope can take many hours. The Night Dig - There were some fine specimens found. Eric Weis of glowhound.com came up with an unusually good SW FL fluorapatite. A few people uncovered some nice, rich hydrozincites. Chris collected with Steve (a long-time Franklin collector) and his brother George; they got some lilac-fluorescing scapolite. It isn't very bright as fluorescent minerals go, but the color is intriguing. The specimen shown below is about 3 inches across. First, here's a picture of it in normal light: 
Now, here's the specimen in short-wave UV: 
Scapolite (Meionite) from Sterling Hill normally fluoresces a magenta color in short wave. The galena-bearing variety from the pits has a different response. It gives a subdued mix of pastel hues: lilac, orchid, blue, gray, sometimes even a bit of tan. It is vaguely reminiscent of some of the subtly-fluorescing "Parker shaft" prehnite specimens I've seen. This material may be similar to the Parker suite of minerals in more ways than one. It seems likely that Pb++ is an activator here, just as it is in most of those Parker Shaft minerals that fluoresce lilac, blue, violet, or peach; the peculiar FL response tends to occur in scapolite whenever there is galena in the rock. Of course, to get the ember-red fluorescence exhibited by the calcite, there has to be manganese as well. At both Franklin and Sterling Hill, it's almost a given that a rock will contain at least traces of manganese. Lead is not really a significant component of F/SH rocks, having occurred only in small amounts in very limited areas of the deposits; on the other hand, manganese is going to be present in just about any rock you're likely to pick up at F/SH sites. Considerable time was taken to make sure the color response of the photo was close to the real-life one. Admittedly, it is not perfect. The real-life FL response of this scapolite, although somewhat dim, is so nuanced and subtle that it is hard to describe, let alone capture accurately with a camera. You could be standing there with three different collectors and you'll get three different descriptions of the color. In fact, Chris, Steve, and George had been talking about this very subject, just about when the tranformer blew a fuse and the lights went out... all except the battery-powered UV lights that collectors were carting back in the pits. It was an eerie moment. |
Shown above: another view of
that scapolite specimen. Notice the zones of different color within
the same mineral, presumably due to different activators. The non-fl.
areas are "dendrites" of manganese oxides / hydroxides (e.g., pyrolusite).
Once again, it's doubtful the camera perfectly captures the color
response, but it's fairly close.Below: A couple more photos (sorry for those of you still on dial-up connections). Shown below is another view of the Passaic Pit. In the foreground is the region where genthelvite was found a few years ago. It's uncertain if anyone found genthelvite on this trip, but it's pretty rare at this locality. In case you're wondering, "where is everyone?", this is what happened. Shortly before Chris showed up to take photos, most of the people had checked out with their poundages and gone up top for the special mine tour. They returned later for the night dig. (Does someone out there have nighttime photos of the dig they'd like to share? ) While most of the crowd went up for the mine tour, a few die-hards remained on the rockpiles. There is one collector crouched down back there. See if you can spot him. 
Above: In the distance a collector stands, looking toward you from the entrance to the Noble Pit. Immediately to the left of that collector (your left, not the collector's), some azurite was found. Sunlight ran out before it was possible to get some photographs back there. What, you thought the photographer was here to take pictures? This was a collecting trip! |
