Field Trip to Contrary Creek – July 26, 2008
“Finding Hot Rocks while Staying Cool”
by Dave Lines
Most of us were old enough to be eligible for Social Security, but it was 90 degrees in the shade, so splashing in the stream made perfect sense. Here were nine members of the Southern Maryland Rock and Mineral Club, who had signed up for a field trip for the last Saturday in July of 2008, and had been told to wear old clothes and old shoes because the location was in the creek. Yes, we did have a few youngsters --- Joshua who is almost 12 and his dad, Dale --- and our young school teacher Jessica. Polly, Jessica, Dale, Joshua and Dave stayed wet almost from the beginning, while Ralph and Mary elected to stay dry and dig the edges of the stream. Larry tried to stay dry, but he was pretty wet by the end of the day.
We had hoped to collect almandine garnets, loose and in mica schist, but anything can happen at Contrary Creek --- near Mineral in Louisa County. After all, the largest gold nugget ever found in Virginia was found right here --- it weighed 9 pounds and is still on display in the Smithsonian. Over 20 other minerals have been recorded in this old mining district, so we kept our eyes open.
When we arrived about 9 a.m., John S. of the Contrary Creek Prospectors Organization greeted us. I had previously stopped by the creek back in May to check the conditions and learn more about the new organization (* for more info, go to www.contarycreekprospectors.org that had leased and posted nearly a mile of the creek south of the bridge on U.S. Route 522. During that visit, I met John who is very friendly and an avid gold panner --- his nick name is “goldveiner”. Anyway, John explained about the creek and repeated his previous offer to let us sign a waiver and go on a tour of their lease. We declined his generous offer and elected to search the creek area near the bridge which was in the bridge right-of-way.
John brought out a large tray of gold nuggets that he had recovered from the creek --- they were GORGEOUS. Four of them were quarter-sized and all were larger than anything we had ever collected there or anywhere else. He even let everyone hold his biggest nugget --- that may have been the highlight of the trip! You should have seen the eyes light up! The exclamations and comments were: “Wow!” - “It is so-o-o heavy!” - “This is neat.” The symptoms definitely looked like the beginning of “gold fever”.
But before we started looking, Dave showed everyone what to look for with some specimens of almandine garnets, crystals of magnetite and pyrite. With that exciting start, we went down the steep path to the creek and spread out. Most chose to carefully examine the abundant loose rock on the beach and in the stream. Some dug in the gravel and screened for garnets.
Carole tried gold panning and stayed at it most of the day.
The stream is acidic due to decades of mining of sulfides --- sulfur and pyrite, especially --- and all of the rocks are coated with a rusty, orange-colored coating which makes all the rocks look the same. The most productive technique appeared to be finding a loose piece of schist (the softer the better) and carefully examining it on all sides and then chipping a piece off with a rock hammer to peek inside. The idea is to find a “bump” or a protruding crystal that indicate that more crystals are inside. When a promising specimen is found, it is saved to await further exposure of more crystals at home by careful removal of the schist with dental picks and similar tools. Another good method is to dig down through the gravel until a layer of heavy clay is reached. This clay had previously trapped loose garnets. Panning out this clay produces tiny to marble-sized garnets of a nice quality with good color and sharp edges.
The bedrock in much of the area immediately around the bridge is a schist --- rich in mica. Some of the schist is as soft as talc and can be scraped with a fingernail, but most is hard and contains minerals such as massive quartz. The soft schist contains the most well-formed crystals, but the contact zone near the massive quartz is very interesting. Actinolite is present in much of the schist and is particularly abundant as flat, thin crystals at the contact zone near the quartz, along with flattened almandine garnets. Occasionally, the actinolite crystals here are thicker and larger, but most of the actinolite crystals here make attractive specimens.
The rocks in the creek are mostly the tailings from the many upstream old mines, so the exact source of each rock is unknown. Nevertheless, many interesting specimens can be found.
Near the end of the trip in mid-afternoon, Dave created a cofferdam along the edge of the creek by building a crude dam and bailing out the water. He dug down about 12 to18 inches through rocks and gravel until he hit a heavy gray clay, then he called everyone who was still there (Larry, Jessica, Polly and Carole) and shoveled some clay into their buckets and gold pans. Everyone then used their fingers to “feel” through the clay to find garnets. Some surprisingly nice, perfect ones were found with the largest about ½ inch in diameter. Also, a several chunks of massive magnetite were found in the overlying gravel as verified with a kitchen magnet. Dave also found a large (40 pounds or so) piece of soft greenish schist which appeared to contain magnetite crystals to ¼ inch.
During our time there, John had set up his power dredge and sluice about 100 feet downstream of the bridge. His panned out a large amount of black sand and found enough gold flakes to find a small vial about ¼ inch deep.
We all said our good byes and thanks to John for sharing his knowledge and, after changing into dry clothes, we left about 4 p.m. --- another fun field trip.