Saturday, December 26, 2009

More Maryland Minerals from Harvard Museum

These days the "haydenite" with "beaumontite" label that accompanies the above picture would read chabazite (in blocky crystals) with heulandite (less recognizable). Haydenite is eponymous with Horace Hayden, an early 18th century dentist, who is credited with its discovery. Early literature depicts haydenite as "a variety of chabazite." Mindat refers to it as a "synonym of chabazite." An easy Internet search reveals a somewhat similar story regarding the nomenclature behind beaumontite/heulandite.

Collected a century plus ago, it hailed from the Harris quarry, one of several long forgotten and filled in filled-in gneiss openings in Baltimore City's Jones Falls Valley. Harvard Mineralogical Museum Curator Carl Francis explained to me in a letter how Harvard obtained this specimen in 1912 as part of the A. F. Holden collection. Holden had purchased it in 1911 for $3 from the legendary mineralogist (and collector/dealer) Lazard Cahn. In his catalog, Holden had described the $3 as "a fearful price for this specimen: bought on Cahn's recommendation." Prettier for sure, but tinier is the chabazite collected here as shown in the micro-photograph at right. It is part of Harvard's vast micromount collection.

Chromian clinochlore is another Maryland piece of note in the Harvard Mineralogical Museum's collection. It's nomenclature is more convoluted than haydenite/chabazite or beaumontite/heulandite. Harvard received both the hand specimen at left and the micromount at right with labels identifying them as nacrite from "Cecil County Maryland near Texas," located just over the state line in neighboring Pennsylvania.

Dr. Francis knew these could not be nacrite, which is a polytype of kaolinite. Because of the locality and purplish red color, he said he would be comfortable labeling them as chromian clinochlore, for which the name kammererite is a synonym. . A more obscure and all but forgotten name for the species is rhodochrome, as referred to in Minerals of Maryland by Ostrander and Price. This book reports rhodochrome both at Bare Hills and Soldiers Delight, also localities in Harford County. In describing the rhodochrome from Maryland's State Line Pits, assuming the pieces shown were collected there, Minerals of Maryland brackets rhodochrome to suggest it's synonymous with penninite. Mindat describes penninite as a pseudo-trigonal variety of clinochlore for which pennine, japanite and miskeyite are additional synomyms. From my photographs, I could not determine whether these crystals were pseudo-trigonal.

I suspect that at one time Harvard's nacrite labels were linked to specimens such as the kaolinite at left. It too, was collected in Cecil County, near Iron Hill, not far from the State Line Pits. Could this particular piece bear nacrite, particularly the brown material at center? The single related reference in the list of Maryland minerals originally sent me by Dr. Francis notes "kaolinite group."

A few other Maryland pieces impressed me as noteworthy. Fred Shaefermyer's flat of Hunting Hill minerals included several rare species including pokrovskite and McGuinnessite. Their photographs are absent here because specimens showing equally well are already in our Maryland Minerals web site's slide shows at Flickr and Picasa. Those slide shows will soon include, however, the Hunting Hill desautelsite image from Harvard's micromount collection as it's shown at right.

Another curiosity from the micromount collection was labeled pharmacolite from the Pinto Railroad Cut in Alleghany County. The 20x photograph at left is insufficient for visual identification. When I first mentioned pharmacolite to Maryland mineral guru Fred Parker, he referred to the occurrence of such a rare arsenate in Alleghany County or for that matter anywhere in Maryland as "just silly." Later after my visit when I emailed him an image, Parker noted that it looked very different from the New Jersey pharmacolite with which he was familiar. The proof, he added would be in an x-ray or EDS analysis, perhaps a worthy undertaking for a Harvard mineralogy scholar.

Another mineral at Harvard I personally had not previously seen from a Maryland locality was vivianite. The substantial specimen pictured at right reached Harvard from an unknown source and was collected at a road cut along Wheeler Road in Oxen Hill, Prince Georges County. The only other vivianite locality I'm aware of in Maryland is a bog at Greenbury Point in Anne Arundel County, where Minerals of Maryland reported an occurrence in grey clay.

Closing out our three post series about The Harvard Museum's Maryland minerals is an example of the species that inspired my original communication with Harvard, namely chromite---in crystals specifically. The micro-photograph at left shows a portion from a hand specimen of Bare Hills chromite from the main gallery cabinet above which a similar looking piece was displayed under glass. Next to the latter had been the glass dish of chromite (actually magnetite) crystals we questioned last summer. The sparkle in this hand specimen enticed me to shoot the macro-photograph at left just before leaving. Regardless of what may or may not have ever been reported of chromite crystals from Bare Hills, this picture suggests their presence. I pass, however, at any attempt to isolate them and place them in a dish.

So there you have it, not only for our Harvard series but for posts during 2009 to the Mineral Bliss Blog. Our best wishes go out to all readers for a happy, prosperous, and wonderfully rocky 2010.

Saturday, December 19, 2009

Harvard Maryland Mineral Update

Mineral Bliss erred in the August 14 post when crediting the Harvard Mineralogical Museum with having but two Maryland minerals on public display. Clearly I neglected to read each of the hundreds of labels, particularly of species that failed to grab my attention or when not expecting to find Maryland minerals. In fact, five Maryland minerals were present.

We missed the humongous translucent lamellar talc that's pictured above. It's from an unnamed locality in Harford County. Harvard received it from an unknown source in 1875. Seeking clues regarding a more specific locality, I referred to my "Bible" for this sort of thing, Minerals of Maryland by Ostrander and Price( 1940, Natural History Society of Maryland). It noted an occurrence of "large green translucent sheets of talc" amidst the serpentine barrens surrounding Mine Fields. That would be my guess, but who knows?

Interestingly, the Museum's Curator Dr. Carl Francis also removed from the locked cabinet beneath the talc a well formed crystal of ilmenite about an inch in diameter. It was embedded in Harford County talc of a hue similar to that of the large sheet. Minerals of Maryland does not mention a locality in Harford County where both talc and ilmenite were known to occur. It does, however, note that in the vicinity of Dublin, the eminent early 19th Century mineralogist Earl Shannon reported ilmenite and garnets in "quartz-fuchsite." With hindsight, I find the resemblance between fuchsite (a variety of muscovite not often found in Maryland) and our talc to be interesting.

Coincidentally, one of the other Maryland pieces on display I missed in August was the ilmenite specimen at left from "near Dublin" in Harford County. It had reached Harvard through the Carnegie Museum in Pittsburgh. Undisplayed in the wooden cabinet beneath it was a similar looking ilmenite crystal, which had also been previously housed at the Carnegie Museum. Its original label showed Chester, Massachusetts, for the locality. Meanwhile, the first of two Harvard attribution labels accompanying it gave the locality as "unknown." A second more recent such label named Harford County's Dinning Rutile Prospect. Minerals of Maryland does not mention ilmenite as occurring at the Dinning Rutile Prospect. This seems curious considering the size of the that crystal, which is pictured at right.

I also overlooked a specimen of coalingite from Hunting Hill. The piece in the picture at left was not displayed in the gallery on either of my visits. Rather, it came from a flat of Hunting Hill minerals donated to Harvard by National Rockhound and Lapidary Hall of Famer Fred Shaefermeyer. Since it closely resembled the specimen in the gallery, I photographed it instead because of time restraints and for the sake of convenience.

Sunday, December 13, 2009

Additional Maryland Minerals at the Harvard Mineralogical Museum

This week's post follows through on the August 14 and October 2 posts about minerals collected in Maryland on display in the Harvard Mineralogical Museum. The August post made the following assertion regarding undisplayed specimens stored in drawers:

With over 4,000 specimens from the Franklin, New Jersey environs, and 7,000 New England pieces, it’s likely that Harvard has additional Maryland minerals. What a treat the prospect of snooping through those drawers. Next visit, additional time will be available, and I'll have researched the protocol.

Such a visit happened this past week, the end result of correspondence regarding the Bare Hills chromite/magnetite controversy discussed in our October 2 post. Thank you again Harold Levey for egging me on to write that questioning letter to the Harvard Mineralogical Museum's esteemed Curator Dr. Carl Francis. Ultimately, it led to his being kind enough to spend the major portion of a busy day showing me where the minerals are kept and arranging for me to photograph the Maryland ones.

In addition to the few pieces displayed under glass in the Gallery, Dr. Francis removed other Maryland minerals locked beneath them in wooden cabinets. From a spacious lab and study area in the Museum's basement, he selected more Maryland pieces from the thousands of specimens in drawers surrounding the desk where he sits in our title picture. After making a special trip to another building where the micromount collection is kept, he walked with me across campus to a house where rows of floor to ceiling drawers filled with hand specimens line the basement. There he made several trips up a ladder to fetch those from Maryland, the most interesting of which we carried back to the museum in a shopping bag for me to photograph.

Upon leaving just before dark, it was clear to me the day's experience was to be a source of substantial content for future Mineral Bliss posts. How welcome to have this material to share during an upcoming six week period where Holidays and extensive travel could easily supersede the kind mineralogical pursuits covered at Mineral Bliss that are normally a routine part of my life. Here are a few likely topics.

  • Maryland minerals on display in the Harvard Mineralogical Museum that were missed during our August visit.

  • Maryland minerals of special interest that are not on display.

  • Curious issues regarding the identification of several Maryland pieces.

Stay tuned.

Saturday, December 5, 2009

A Classic Pennsylvania Calcite

The Mineral Bliss post from November 14, 2009, which described an escorted visit to the Delaware Mineralogical Museum, made the following statement: "I've deliberately refrained from mentioning one Pennsylvania specimen in particular to share its story as the sole topic of a future Mineral Bliss post."

It was the calcite specimen shown in the above picture from the Delta Carbonate Quarry, now known as the York Building Supply Quarry, in York, Pennsylvania. With a main crystal measuring about 4 1/2 inches across, I've never observed a more appealing example of this classic genre. Upon learning from the Delaware Mineralogical Museum Curator Sharon Fitzgerald that its original source was one of my favorite collector/dealers, I immediately decided to contact him.

Eric Meier of Wilmington, Delaware, is pictured at left behind tables of his inventory at the Delaware Mineralogical Society's show this past March. Trading as Broken Back Minerals, he was among the busiest dealers there. Likewise, at the September Gem Cutters Guild of Baltimore Show in the Howard County Fairgrounds, November's Roanoke Valley Gem and Mineral Show at the Salem,Virginia Civic Center, and other East Coast events. He carries substantial regional material. His prices are quite reasonable to begin with and become increasingly so for customers who purchase in quantity.

Eric informed me that a threesome also including his friends Bill Longacre and Joe Hoffman collected this magnificent calcite specimen together in 1993. They were at the bottom of the quarry when Hoffman noticed a small hole about 25 feet up a scalable slanted wall. By chiseling away at the brecciated limestone surrounding the hole, they succeeded in opening up a pocket completely lined with crystals. About eighteen inches high and ten to twelve feet wide, the pocket tapered back approximately eight feet. Once they'd opened the pocket, removing the crystals therein became more difficult. Limestone that was not brecciated surrounded them. The men shoved a blanket into the pocket to protect what crystals they could dislodge, then hammered and chiseled away. When finished, they agreed to divide the booty and rolled dice for first pick. Eric rolled a double six for the piece now in the Delaware Mineralogical Museum. It required minimal cleaning.

Skip Colflesh, whose ruizite find at Cornwall, PA, was the subject of the June 13 Mineral Bliss post, also collected large quantities of calcite at this York locality between 2000 and 2002 in the company of fellow legendary Pennsylvania collectors Bryon Brookmyer and Bob Weaver. Skip authored a well illustrated article about the genre that appeared in the September/October 2002 edition of Rocks and Minerals. In a recent Email to me, he mentioned "crystals up to ~8" and the subsequent discovery in 2003 of a pocket with even more diverse crystals.

The crystals are often twinned or stacked. Sometimes they appear ball-like. Their forms range from rhombs to prisms to scalenohedra. This diversity along with a distinctive orange/ honey/ amber coloration distinguishes them. Similar crystals have been collected at another nearby York Building Supply owned quarry known as the Thomasville Quarry. While both localities have been off-limits to collectors for years, plenty of calcite from them remain available on the market and grace both museums and personal collections.