Uncommon Finds in Harford County, Maryland

Recently, an email came in from a Mineral Bliss
reader named Deb who lives near the northwestern corner of Harford County, Maryland. She said she had found microscopic flakes of gold in a nearby creek. She also reported having collected a large ilmenite specimen amidst rocks directly across the road from her house. Rutile, she said, is "everywhere out here." Deb was born in this area. She has lived hereabouts most of her life and collected minerals since childhood. Needless to say, I was intrigued and promptly made arrangements to visit.

Shortly after my arrival, Deb suggested we go for a drive. Heading east on Maryland Route 136 , we drove through an area where quartz had frequently intruded amidst late Precambrian Upper Pelitic (Wissahickon?) schists. The quartz hosts all the ilmenite of which Deb had spoken and once hosted the rutile crystals, most of which have separated and typically occur loose in alluvial deposits and plowed fields. Regarding the latter: "Some fields have a lot of rutile,"Deb explained, and some don't have any." She drove me by a cornfield very close to the Pennsylvania Line where the owner had given her permission to collect. Though mostly covered with remnants from last summer's crop, enough stones were visible for us to pluck a few rutile crystals and two pieces of ilmenite with quartz.

The geology in this part of Harford County is fascinating. Farther east on Route 136 near Whiteford, Deb pointed out woodlands to the north that host a large opening that was once the Williams Slate quarry. Circling the immediate area of this opening , a geologic map of Harford County shows a ring of rock referred to as the Volcanic Complex of Cecil County. I surmise that the site of the old Cardiff Serpentine Quarry, once noted for its Verde Antique building stone, sits somewhere within the boundaries of that ring about a mile farther north at the Pennsylvania line.

We continued driving east on Route 136, passing the crossroads of Dublin, from which a short road leads to sites where talc was once quarried in large steatite openings. Uncertain regarding accessibility, we continued southeast on Route 136 for another mile to Route 1. There we turned left, and headed northeast across the the bridge over Conowingo Dam into Cecil County. Near Conowingo, Deb quickly led me to a spot where we found a small piece of rhyolite from that county's aforementioned and eponymous Volcanic Complex. Though the country rock here was Port Deposit gneiss, the origination of rhyolite pieces sparsely scattered on the ground been traced to a location within Cecil County's scattered Volcanic Complex somewhere between here and Northeast, Maryland. It was my first encounter with Maryland rhyolite.

From here we headed back to Deb's house where she had yet more that was interesting to show me. In a vial with those sparse flakes of gold she had panned from the stream near her house was a silver coloured nugget, measuring a fraction of a millimeter, that looked like platinum, which would certainly be very unlikely. Having since taken time to study its photomicrographic image, however, it screams micrometeorite! We're eager for word from any readers with different ideas.

In a lifetime of collecting, Deb has come up with a lot of interesting material from other parts of Harford County. Though hardly known for its pegmatites, Deb was at hand about 20 years ago when the construction of a driveway uncovered a small pegmatite outcrop within a mile of where Route 1 crosses Deer Creek. It was here that she collected the beryl crystal pictured at left, the only example of the species that I've seen from Harford County. The same locality also yielded the specimen at right, which appears to be two columbite crystals in feldspar. Assuming a correct visual identification, this is not only the sole columbite I've encountered from Harford County, but from anywhere in Maryland. Deb also collected the chalcedony pictured at left from a spot close by where the local rock was metagabbro.

Finally, and again at least several decades ago, Deb uncovered an amethyst crystal on a long since built over farm on the south side of Route 1 very close to where it crosses from Harford into Baltimore County. Although the Natural History Society of Maryland's 1940 Minerals of Maryland publication by Ostrander and Price reports amethystine drusy quartz from Mine Fields, this is the only find of an actual amethyst crystal that that I'm aware of from Harford County. Since her crystal was marred with its share of dings, Deb had cut from it the pendant pictured at left next to the remains of the original crystal.

Interestingly, all of the species Deb has found that seem so unusual for Harford County are present not far across the Mason-Dixon Line in Southern Pennsylvania, where the Piedmont geology is relatively similar. It should also be safe to say that Pennsylvania, over the years, has attracted a lot more collectors to uncover them.

Tucson: 2012 and Every Year

Each year from the final Friday in January through the second week of February, the city of Tucson, Arizona hosts the world's premier extravaganza featuring minerals, gems, beads, lapidary supplies, fossils, and meteorites. It all takes place in motels and tents all over town and culminates with "The Big Show," which happens at the Tucson Convention Center from the second Thursday of February continuing through Sunday. Regarding minerals, each year's show has a theme. The 2012 theme was "Minerals of Arizona." Otherwise, it's much the same from year to year. The usual vendors set up at their usual spots, while the times and locations of the lectures, banquets and symposia change little.

Mineral people come to look, sell, learn, network, schmooze, and most of all to purchase. Buyers who arrive when the action begins in January are likely to have first shot at new finds and other much in demand material. Prices of specimens can range from a couple dollars to well into six, even sometimes seven figures. Differences in price of pieces that would appear to be of similar value can also cover a vast range. The prices of some specimens can increase over the course of the two week period as they change hands from one dealer to the next. Prices can also head lower as well, especially at the end of the show when some dealers would rather accept less cash than haul home certain rocks. The word "keystone" is heard frequently. It means half price. "Double keystone" is where a price already cut in half is halved once again.

Prior to the Big Show, the nexus of the mineral action is at the enormously spread out Hotel Tucson City Center (formerly Inn Suites) at 475 North Granada. Another much smaller venue not far away but worth checking out is the Mineral and Fossil Marketplace at Oracle and Drachman featuring some respected mid-range dealers who operate from tents. Also close by at Speedway and Main are yet more tents manned primarily by Moroccans. Along with fossils, they have flats and flats of such signature material from their country as malachite, azurite, erythrite, cobaltian calcite, cerussite, barite, skutterdite, quartz geodes, epidote, pyrolusite, goethite, and occasional yellow apatite---though not too much else. Across town, the Quality Inn on Benson Highway is loaded with mineral dealers, mostly from China, India, Pakistan, Afghanistan, and Russia. Additional activity extends for at least a mile in motels along the service road paralleling I-10 as it passes downtown Tucson. Though mostly gem and fossil oriented, some great deals on minerals are occasionally available from a relatively few mineral dealers who typically specialize in but one or two species. The same is true at other venues, such as the Kino Complex and Tucson Electric Park.

The only truly unique event during the period leading up to the Big Show happens the previous weekend at the Westward Look Resort. On Saturday, a great private collection graces the main lobby. On Sunday night, following a social hour, there's a presentation by someone accomplished and well-known in the mineralogical arena. Featured this year on Saturday was the collection of Ron Gladnick. On Sunday evening, the legendary 94 year old Ed Swoboda presented an overview of a long life devoted to gems and minerals. Most definitive of the Westward Look Show, however, is what goes on in a couple dozen adjoining private suites where just about every well-known high-end mineral dealer on the planet has set up shop. The quality and beauty of the magnificently displayed minerals for sale are no less mind-boggling than the numbers on their price tags.

With the Big Show underway on Thursday, the Convention Center becomes the focal point, although business continues at other venues around town. Mineral specimens from various collections, both public and private, are displayed in cases, mostly in the northwest portion of the main hall. Dealers of minerals are located near these displays as well as throughout the western part of the main hall. Though differences in price for similar specimens continue to be wide as ever, the popular perception is that everything costs more at the Convention Center. Notwithstanding, plenty of bargains are around for those with the wherewithal to seek them out.
The Big Show is also the site for lectures, programs and seminars. World famous gem and mineral photographer Jeff Scovil, who withholds no secrets regarding his techniques, gives a two hour instructional presentation each year on Thursday. This year he concentrated on creating backgrounds for photographing minerals.

The Arthur Roe Micromount Symposium takes place all day Friday upstairs in the Turquoise Ballroom. In addition to the speakers (I caught a great illustrated talk by Bob Meyer on the microminerals of Tiger, Arizona), are numerous "giveaway tables" with flats and egg cartons of material sorted according to locality. It's there for the taking, and most of it begs for scrutiny beneath the scope for brilliant, rare, and beautiful treasures.

In the adjoining Crystal Ballroom, a succession of speakers holds forth all day, most of them covering topics related the given year's theme, this year minerals of Arizona. The scene here is much the same on Saturday as Friends of Mineralogy, the Tucson Gem and Mineral Society, and the Mineralogical Society of America host an annual symposium that once again features renowned speakers, most covering topics related to the show's theme.

Although the Big Show continues through Sunday, what for many attendees is its climax happens Saturday night over cocktails, an auction, dinner, and ultimately the presentation of numerous mineralogical awards. The grandest of these is the prestigious Carnegie Mineralogical Award. This year's recipient was Dr. Jeffrey Post, Curator-in-Charge of the mineral collection at the Smithsonian. Also notable is the level of ceremony recognizing the mineralogical accomplishments of young people. This has much to do with the longing of older mineral folks to see their hobby perpetuated. They sense that in this modern age of technology, diminishing numbers of youngsters are getting involved.

Next year's Big Show theme will relate to the many forms, habits, and localities for the common but often spectacular mineral fluorite. Otherwise, we can feel assured that all will be much the same as it was this year and preceding years. For sure Tucson will continue to provide a world class opportunity to enjoy, view, and learn about minerals. A few that I observed with particular awe can be seen at this link.

Opal at Bare Hills

Most likely opal is not uncommon as a coating on the serpentinite rock at Bare Hills along either side of Falls Road about a mile north of the Baltimore City line. Yet, I doubt that opal is on the radar of those prone to collecting here. At least, I've never heard anyone mention it, nor had I ever seen any Bare Hills opal. My only awareness of opal at Bare Hills was that Ostrander and Price's long out of print Minerals of Maryland (1940, Natural History Society of Maryland) named it as one of the species occurring at the two adjacent and long abandoned Bare Hills Serpentine Quarries as well as the surrounding barrens once dotted with chrome pits.

For the sake of reference, the image at left shows the westernmost and better recognized of those two former serpentine quarries along Falls Road. It was a good collecting spot until fenced off and declared off-limits by its owner, the Gerstung Inter-sports facility located at the end of Coppermine Terrace*. More accessible on the other (east) side of Falls Road, its presence mostly obscured by vegetation, is the second abandoned Bare Hills Serpentine Quarry. The ultramafic rocks comprising its talus, while not as interesting as the rocks I remember from years ago at the western opening, yielded my opal (var.) hyalite.

A dull blue-grey glint on a rock encrusted with tiny whitish globular dots caught my eye. Observing through the loupe, I assumed the dots to be magnesite or hydromagnesite, which ubiquitously forms massive coatings on similar rocks throughout the Bare Hills area. The globular presence was distinct enough that it prompted me to bring the piece home for a look under the scope. The right side of this post's title image shows the surface of this rock at 40x. No question that the coating is opal, whose obscurely reported presence at Bare Hills had mystified and fascinated me for more than 50 years.

Since the appearance of this rock was so similar to hundreds of rocks hereabouts, I suspect that opal may not be that elusive at Bare Hills. This certainly was not the first time I'd seen rocks in the area that were visually similar, at least at first glance. Otherwise, except for occasional birdseye chromite in weathered serpentine rocks along with a few veins of chrysotile, there seemed less that was likely to interest collectors than I recall from years ago at the quarry on the other side of Falls Road and the chrome pit dotted serpentine barrens surrounding it.

Though off-limits where not built over, my hunch is that those barrens on the west side of Falls Road, unlike those on the east side of Falls Road that surround the site of my recent visit, always were and still could be more interesting. They will be the topic of a Mineral Bliss post at some point in the future.

*It could be that the name of "Coppermine Terrace" was conceived in ignorance. In its entirety, Coppermine Terrace passes exclusively through serpentine barrens formerly worked for chromium only. The site of the former Bare Hills Copper Mine is approximately two miles away and set in a completely different landscape.