Maryland Mineralogy Presented at Rochester Symposium

• Note: Readers are encouraged to check out the Mineral Bliss Podcast about the Rochester Symposium.

Beyond the State or local level, a presentation such as Fred Parker delivered on the morning of April 16 at the Rochester Mineralogical Symposium has long been overdue. As Parker expressed early in his talk, Maryland is "the Rodney Dangerfield of the mineral world." He also credited amateur Maryland geologist Jeff Nagy for much of the presentation's information and perspective. Nagy and Parker have been working together on research intended for an updated printing of Lawrence R. Bernstein's Minerals of the Washington, D.C. Area, which was originally published in 1980 by the Maryland Geological Survey.

The presentation was in three parts as follows:

• A short history of mining in Maryland


• Review of a geological map of Maryland


• A slide show of relevant Maryland Minerals
  

MINING HISTORY

Despite reports that Captain John Smith recognized the presence of bog iron ore in sedimentary deposits near the Chesapeake Bay, mining did not begin in Maryland until 1740 with patents for iron and copper. Thereafter, Maryland mined iron in substantial quantity, some that was used in the manufacture of munitions during the American Revolution. Pre-revolutionary dumps are still accessible at Mineral Hill in Carroll County. Maryland was also a significant producer of iron for the War of 1812

By the 1840's, Maryland had become one of the world's leading producers of chromium. The ore was mined at Bare Hills and Soldiers Delight in Baltimore County, near Cooptown in Harford County, and near the Pennsylvania State Line in Cecil County. Soon after the Civil War, Maryland was also a source, though never on a major scale, for a variety of other metals including gold, lead, manganese, and zinc. An accompanying slide, possibly the only known photograph of a facility in Maryland where metals were mined, pictured a manganese operation along the Potomac River about five miles upstream from Harpers Ferry. Maryland also produced such nonmetallic materials as mica beryl, feldspar, clay, talc, and coal.

MAP OF PERTINENT GEOLOGY

A map with colors explaining the geology inherent to the state's rock forming minerals was the focus of the presentation's second segment. It emphasized Maryland's central portion, which is more favorable to the pursuit of mineralogy than the coastal plain to the east or Garrett County at the western end of the state. Parker noted the following:

• Formations of diabase still being quarried along the Susquehanna River near Havre de Grace.
• Serpentine deposits that appear and reappear in a northeast to southwesterly path from the State Line in Cecil County in the northeast to Montgomery County in the southwest with reappearances in Harford, Baltimore, and Montgomery Counties.
• Miocene sediment deposits along the Patuxent and also the Potomac Rivers that have yielded an abundance of high quality gypsum crystals.
• The Baltimore gneiss, a metasediment that occurs sporadically in more spots than could be shown on the map. The Baltimore gneiss hosts many pegmatite intrusions that Parker described as "really quite fascinating in Maryland."
• The Wakefield Marble accounts for both the active Medford and Portland Quarries in Carroll County as well as the long closed Liberty Mine in Frederick County, once Maryland's biggest producer of copper.
• Parker noted the existence of Paleozoic sediments between the Wakefield Marble and the Precambrian metavolcanic Catoctin and Braddock mountain ranges. He described the latter as the source of excellent quartz veins near where these mountains approach the Potomac River.
• Immediately west of the mountains is a region of limestone, shale, and sandstone extending into Pennsylvania and Virginia. It is the source of similar minerals in all three states.

SELECTED MINERAL OCCURRENCES IN MARYLAND

This was the most extensive segment of the presentation. The minerals were shown pursuant to their localities in conjunction with the geological map. Most can be seen on the Picasa slide show at the Maryland Minerals web site. Some, of these minerals also appear in posts on this site from July 18, 2009, May 2, 2009, and April 25, 2009 . Here are some of the highlights noted:

• Approximately 250 different mineral species have been collected in Maryland.
• Maryland is the type locality for one mineral, carrollite, which was discovered at the Patapsco Mine in Carroll County, for which it is named.
• Significant quantities of tourmaline (variety schorl) showing several different habits including terminated crystals up to six inches in chlorite schist have been collected at the Maryland Materials Quarry in the diabase formation along the Susquehanna River.
• As noted in the geological segment, the Miocene sediment deposits at Chancellors Point in St. Mary's County and Fort Washington in Prince Georges County have produced gypsum crystals of magnificent quality.
• Garnets up to two inches in chlorite schist are abundant in a wooded area of Baltimore County about 22 miles north of Baltimore City.
• What Parker belives could be Maryland's most prolific beryl locality is on the banks of a river near the Baltimore/Howard County line at a locality that he and Nagy refer to as the "Waterside Prospect." It is currently covered with water.
• A particularly interesting slide showed monazite, which is rare in Maryland, from one of several long closed mica mines in Montgomery County.
• Another slide displayed quartz crystals from a "lost" locality in Clarksville, Howard County, which Parker rediscovered when combing the digs for a housing development that ultimately obliterated the locality.
• One of the most spectacular slides was of an historic botroydal malachite specimen from Carroll County's Patapsco Mine.
• Two slides of Maryland gold in quartz, one from Montgomery County, another from Carroll County, attracted major interest.
• Parker cited the Medford Quarry in Carroll County as Maryland's most prolific locality. He emphasized its abundance of diverse calcite pockets and also noted it as the source of some rare minerals. As an example, a slide of micro lanthanite crystals from a one-time find was shown.
• The Portland Quarry at Union Bridge in Carroll County, just a few miles from the Medford Quarry, received the distinction of being Maryland's most unpredicable locality Among the slides with which Parker demonstrated this point was one of a transparent yellow wulfenite specimen from a find in the 1970's.
• Predictably and appropriately, he reserved for the Hunting Hill Quarry in Montgomery County the honor of being Maryland's most mineralogically important locality. Citing the gemmy grossular associated with its serpentine and rodintine, he compared Hunting Hill's geology to Vermont's Eden Mills locality. He then showed slides of some of the seventy one different species that have been collected at Hunting Hill. A slide of xonotlite crystals was particularly noteworthy.
• An expecially spectacular slide showed quartz crystals that were collected in the soil near Burkittsville in Frederick County prior to the Civil War.
• Further west in Paleozoic limestone near Hagerstown in Washington County, Parker noted that one of several quarries that are quite similar to one another has produced attractive strontianite as well as native sulphur and celestine.
• Further west in Washington County, Parker recognized the Pinesburg Quarry for its blue barite crystals and showed a slide of an exceptional specimen from his personal collection.
• The final and westernmost locality he named was Savage Mountain near Frostburg. Once mined for its fire clay, it was one of Maryland's most popular collecting localities in the 1930's and 1940's. Savage Mountain is best known for geode like nodules filled with crystals of siderite and barite. A highlight was a slide photographed by Yours Truly of such a nodule bearing spectacular needles of millerite up to an inch long.
• Parker concluded his presentation with an image of that he described as a "doorstop," namely serpentine and chromite with an historic label attached to it. The idea was to make the point that despite the initial impression of numerous mineral people, Maryland's mineralogy amounted to more than than simply these two species.

Note to readers: The next Mineral Bliss post is scheduled to appear at the end of the second week of May, 2010

Panning for Anatase in Harford County: Part II

Ev parked along the country road paralleling Falling Branch opposite from where a small rivulet flowed into it from the adjacent wooded hillside. We removed from his trunk our waders, rubber gloves with cotton gloves to wear under them, two shovels two buckets, one with 1/4 holes drilled into the bottom third, pans, Ev's "sucker," and baggies. Casing out the stream, Ev pointed out and expressed his preference for spots where the velocity of the water changed, better in front of rocks around which the current swirled with at least some downward motion. He was also eager to pan at the mouth of the small rivulet

As I watched from the bank, Ev waded into the stream, secured his buckets, one placed into another for drainage from top to bottom, and began digging beneath the downstream side of a rock the current was circumventing. For each load, Ev extended his shovel all the way down to scrape the bedrock where gold, as the heaviest substance in the stream, tends to gravitate. Anatase, though nowhere near so heavy as gold, has sufficient specific gravity to do likewise.

After tossing away the larger rocks, Ev turned the linked buckets sideways at an angle to the current to sieve the sand and smaller pebbles to the bottom bucket through the holes in the top one. After repeating the process several times, he transferred the contents of the bottom bucket into the pan.

Since some of the additional sand remaning in the stream beneath the rock ledges was likely to be relatively heavy, Ev scraped the area, seeking out small pockets with a screwdriver before going to work with the "sucker" he is holding in the image at right. He covered the smaller tube with the larger one and placed the tip under the ledge. While holding the smaller tube in place, he pulled on the larger one to suck out water in which additional sand was dispersed. This he poured into the pan.

The next step was the actual panning to reduce the pan's contents to heavy "black sand," much of which would prove to be magnetite. To accomplish this, he held the pan in the stream and swirled its contents back and forth. With assistance from a reasonably mild current, the lighter sediment washed away while small pebbles he removed by hand trended toward the top. A layer of lighter sand settled beneath them. The heavier black sand, meanwhile, gravitated to the bottom of the pan or became caught in the cavities built into its side. This work takes a few minutes and can be tedious. Upon completion, Ev placed the remaining black sand into a marked baggie.

Ev then repeated the entire process where the rivulet entered Falling branch. When finished, he suggested I grab a shovel and try my luck in front of another rock surrounded by swirling current. Albeit with much less finesse, I followed all the previously described steps and eventually produced a small quantity of black sand. We placed it in a marked baggie and headed back to Ev's house, put the sand in his oven to dry, and drove into Jarrettsville for lunch.

When we returned in about 45 minutes, the sand had dried. After removing with a magnet the predominant magnetite, we placed what remained into three film canisters. The fruits of our morning's labors were now ready for observation under Ev's microscope. Checking a few small samples, we found fragments as well as crystals of garnet, minute cubes of goethite after pyrite, specks of pyrite, possibly some beryl, a few black octahedra (Were they chromite? Why didn't I think to retrieve that magnet?), and occasional rough grains of anatase. Ed removed the most interesting material with a special pair of microscopically tipped tweezers. After two hours, we had examined but a small fraction of the sand.

A week has now passed, and Ev just emailed me that he has finished going through the sand from the first two of our three digs. While his second dig at the mouth of the small rivulet hadn't yielded much, his first dig of the day ended up producing "210 little pieces of blue, bark blue, tan (the most), and yellow (the least) anatase," including 3 dark blue double pyramids (all broken),and two sky blue very small flat topped pyramids (complete), and 2 dark blue flat plates.

Meanwhile, I've been out of town over this past week and before leaving had time to check out but a small sprinkling from the film canister bearing the fruits of my own first attempt at panning. A portion of of it is shown at left. Eyes still relatively untrained for spotting anatase, my inclination had been to delay going through the rest until the list of activities on my busy to-do list slowed down a bit. After receiving Ev's recent email, however, a few of the them could have to wait.

Gold and Anatase in Harford County, Maryland

Rarely does a topic more newsworthy to Mineral Bliss sensibility present itself than the contents of an email received recently from Ev Smith. Included were the above image of anatase crystals he panned from Falling Branch in Harford County Maryland as well as photos of larger specimens of rich chromite and serpentine minerals (right) that he collected near Cooptown. I responded within minutes and soon managed to wrangle an invitation to go panning for anatase with Ev a week later in Harford County's Falling Branch.

Like so many who pan for gold in the Mid-Atlantic, Ev got started with his hobby under the mentorship of Jack Nelson, the late and legendary regional "godfather" of panning. They panned mostly near Great Falls in Montgomery County. This is where Rock Run and other small streams flow through woodlands where gold mining operations were ubiquitous between 1864 and 1940. After Jack's death from cancer in 2002, Ev began panning for gold in streams closer to his home near Jarrettsville in Harford County. He is the only person I know of to actually find gold in Harford County. Most of the flakes in the image at left, Ev panned from Harford County streams. The larger nugget, in the top left corner of the picture, is from a small stream in Pennsylvania just over the Maryland line.

As a protege of Jack Nelson, it didn't surprise me that Ev would look for more than just gold in the material he panned from these streams. Jack was also an avid micromounter and had discovered amidst heavy mineral concentrates from streams in Montgomery County and elsewhere the first cubic garnets ever to be reported and identified. Aware that some of the grains of sand he was extracting were likely to be gem minerals, Ev made a practice of bringing home in baggies the sand that remained at the bottom of his pan at the end of the sifting process. Encountered were rutile, schorl, garnets in hues running a gamut from lavender to deep red, minute cubes of goethite pseudomorph after pyrite, and various other grains of sand not as easy to visually identify. Very likely, they could include, beryl apatite, zircon, and zoisite. The less common anatase was a later find that became apparent after Ev isolated several uncommon anatase grains with their crystal habits intact. More typically the anatase occurs in broken fragments like those in the image at right.

I arrived at Ev's house on Monday, April 5, with a borrowed pair of waders. In short order, we were en route to Falling Branch. Along the way, Ev pointed out to me where he had collected the chromite and serpentine minerals. Minerals of Maryland had described the locality as "serpentine barrens" with numerous chrome prospects in"Coopstown and Vicinity." Assuming this would be a landscape similar to Soldiers Delight or Bare Hills in Baltimore County, I had previously driven through the area looking without success. Instead, what Ev pointed out to me was a lush woodland with a variety of tall trees. For access, permission would need to be obtained at several houses, and Ev was no longer certain which ones. Ev also told me about a copper prospect just a short walk away that was not mentioned in Minerals of Maryland where he once collected some copper bearing minerals.

About ten minutes later, we pulled off a country road along Falling Branch not far from where it empties into Deer Creek. With our waders, a couple of shovels, two large white white buckets, one with 1/4 inch holes drilled through its bottom half, pans, and Ev's "sucker," we headed toward the stream. Next week's Mineral Bliss post will be about our experience.