Wednesday, June 4, 2014

The Mineralogical Legacy of Baltimorean Robert Gilmor

The important collection described below is the subject of a document excerpt  recently transmitted to me by John S. White, past Curator-in Charge of   the Smithsonian's Division of Mineralogy. He received it from Dr. Johan Kjellman, curator of the mineral collection at Uppsala University, Sweden. Dr. Kjellman had been researching crystal models and was interested in those that Albert Hauy had originally intended  for presentation to the Emperor of Austria. The excerpt below is  from The American Journal of Science and Arts, Second Series, Volume 6, November, 1848. In the note to which it was attached, Mr. White stated:  "Turns out that the old gentleman was Robert Gilmor (1774-1848) who, interestingly enough, was a Baltimorean. "

It did not take long for me to determine that in 1814, Mr. Gilmor published "A descriptive catalog of minerals occurring in the vicinity of Baltimore"  in  Bruce's American Mineralogical Journal, Vol.1, 1813, pp. 221-223. Therein he enumerated 43 different minerals found within a 14 mile radius of the city. Although Google had digitized this publication, the pertinent pages were missing from those that appeared on line. 

A Friday afternoon visit to Johns Hopkins University's Milton Eisenhower Library revealed that the publication we were seeking was available there on microfilm. The librarians were kind enough to locate it for me over the weekend, and by Monday copies were in my email. 

Here are some  items that proved to be of particular interest:
  • "Native Magnesia:" From Bare Hills, obviously this is magnesite. "Is it not a carbonate of lime combined with magnesia?" Mr. Gilmor pondered. Even today, massive magnesite is quite common throughout the Bare Hills serpentine barrens. However, for it to be in crystals "accuminating to a dihedral summit---insulated, pure white and (or) transparent,"  is unheard of. 
  • Corundum:  "An hexahedral crystal an inch in diameter was also found at Bare Hills, which in all its external characters corresponds with corundum, as described by Hauy; but the writer considers it doubtful"  Since then, corundum has been reported where pegmatite injects serpentine in other parts of Maryland. As a pegmatite dike adjoins the serpentine at the northern extreme of Bare Hills, the possibility of a corundum find seems realistic.
  • "Staruotide is found in hexiahedral prisms with dihedral summits on the Falls Turnpike, 7 1/2 miles from Baltimore." This could be the same material  as collected by Bob Simonoff and very kindly confirmed for us as staurolite by Professor Emeritus Peter Leavans at the University of Delaware. It was the subject of our July, 2011 post 
  • "Disthene:"--"or Cyanite, (lamellar) of a pale green (rarely blue) is found in a micaceous rock about 20 miles from town on the Falls turnpike, at Scotts Mill, 7 miles from the York Turnpike. The crystals are large and small, many of them 4 and 5 inches in length."
  • Galena: "Found in a small vein in quarries about the first Falls Turnpike gate on the west side of Jones' Falls, accompanied by black lead ore and blende of sulphuret of zinc.  It is also asserted to be lately found in a large vein within 7 miles of the city, but the direction is kept a secret. The specimen seen by the wriiter, and said to come from the spot, was a large mass of galena." 
We have posted the document on our Maryland Minerals web site .  

Meanwhile, we have just received word from John White that Wendell Wilson, Publisher and Editor in Chief of Mineralogical Record, (which Mr. White founded in 1970) is interested in putting together an article about Mr. Gilmor, especially if he can come up with at least a couple of photographs of minerals bearing his label. Mr. Wilson's research suggests a possibility that perhaps one or two significant specimens once owned by Mr. Gilmor that were not included in the collection being sold in 1848 could have remained in Maryland. We are currently investigating that possibility. While the likelihood of locating these specimens is remote, our efforts could open new windows on mineral specimens collected in and/or housed in Maryland. 

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