Penn Minerals! - Classic Minerals and More from Pennsylvania

By Jay L. Lininger

Philadelphia's early interest in natural science flourished in the incubator of Quaker tolerance and desire for knowledge. Coupled with the botanical and geological diversity in the mid-Atlantic region, this interest set the stage for the birth of science in America. Much has been written of this formative period, and recorded in the proceedings of the two early institutions established to promote the development of science-The American Philosophical Society (founded 1743) and the Academy of Natural Sciences of Philadelphia (founded in 1812). They attracted many of the top scientific thinkers in the new nation, and through their efforts, several new disciplines were born and dispersed throughout the United States. One of these is the science of mineralogy.

Mineralogy in the Philadelphia Tradition

As early as the 18th century, mineralogy was a robust science, forged in European academic institutions and mining schools in London, Edinburgh, Paris, Heidelberg and Freiburg (Germany). Interest in economic minerals, particularly of valuable metals, was increasingly a motivating force for the advancement of the science. Understanding the origins of minerals improved one's chances of finding them. A select group of immigrants who had such knowledge relished the opportunity for mineral discovery in the new colonies. William Penn himself recognized the enormous potential for minerals in his great land grant. He attempted to locate rich mineral deposits, and reserve them for his heirs.

After the Revolutionary War, Philadelphia, the cradle of freedom in the new nation, rapidly became the cradle of science as well. Though textbooks were limited, a free exchange of information became the catalyst for scientific knowledge. New ideas and discoveries were recorded and published in the proceedings of the American Philosophical Society and the Academy of Natural Sciences. Much of the new knowledge revolved around mineralogy, for in this era it was closely allied with the science of chemistry. Serendipitously, the geology of the Philadelphia area was rich in minerals, so the fledgling scientists did not need to travel very far to find and study them.

As public interest in mineralogy grew in the Philadelphia area, each region of the city was scrutinized to determine what species could be found. Situated in an area of complex metamorphic geology, the Germantown area proved to be productive for early mineralogists.

It is worth noting why exceptional minerals were frequently found throughout the area. An ancient metamorphic rock type known as the Wissahickon Formation was host to an abundant volume of small localized volcanic intrusions which had migrated upward from the earth's mantle. These intrusions, often referred to as pegmatite swarms, bore hot mineralizing solutions that were rich in mineral-forming elements. Another ultramafic rock type seen in the Germantown area was serpentine. The pegmatite swarms, the serpentine and certain facies of the Wissahickon schist became ideal mineral-forming environments. As the course of city development extended outward, new mineral discoveries in Germantown were made on a regular basis.

With the establishment of the Academy of Natural Sciences of Philadelphia in 1812, the science of mineralogy received a major boost. The first Academy president was Gerard Troost, a Dutch scientist trained in chemistry, mineralogy, and medicine. Other founders were John Speakman, a Quaker apothecary, John Shinn, a manufacturer of chemicals, Reuben Haines, a Germantown resident, and William Maclure, a wealthy Scottish merchantgeologist-reformer; all were devotees of mineralogy and geology. Not long after, a cabinet of minerals was established at the Academy.

Natural science in general came into vogue as an avocation during this era. The collecting of geological and botanical specimens became an avid pursuit, and private collections of these items were viewed as a form of cultural enrichment. Minerals in particular, because of their crystal structure and beauty, were quite popular. Unlike botanical specimens, their preservation was easier and more permanent. Near Chester, a Quaker family by the name of Leiper opened a series of quarries which produced dimension stone (stone quarried in blocks of specific size and shape) for the elegant homes and commercial buildings in downtown Philadelphia. The pegmatites within these openings produced a series of exceptional minerals, particularly beryls, garnets, feldspars, and tourmalines of great beauty. They soon began making their way to collections around the country. Further west, the Perkiomen and Ecton lead-copper mines in Montgomery County, began producing an interesting series of metallic minerals. Near Media, in Delaware County, abundant amounts of beautiful, deep purple amethyst crystals were also being recovered from the soil on surrounding farms. These locations served to further stimulate an already active interest in the local mineralogy.

Various members of the Academy of Natural Sciences were active in assembling private mineral collections during the first half of the 19th century. Among the most well-known were Isaac Lea, Samuel Ashmead, George Carpenter, and W D. Hartmann. These men donated many fine specimens to the Academy cabinet, but the gift of the William S. Vaux collection of 16,000 specimens, along with an endowment of $10,000 to sustain it, suddenly propelled the Academy into a leading repository. About that same time, the American Philosophical Society donated its collection as well. Thus well secured in its holdings, the Academy managed to hold a leading position amid the other rising institutional collections at Yale and Harvard.

The post Civil War era brought an unprecedented industrial expansion to the northeastern states, and Pennsylvania entered its prime as a mining state. Coal and iron fueled the economic engine, but other metallic wealth, mainly zinc, nickel, and chrome mining flourished in the Commonwealth. Interest in minerals reached its apex, in a period which Smithsonian curator Paul Desautels described as "the golden age of American mineralogy."  Mineral collecting, once the pursuit of wealthy gentlemen, had now become a pastime for ordinary people.

Mineral Collecting in the Germantown Area

In 1892, a group of Philadelphia mineralogists met to found a club which would cater to the interests of amateur mineral collectors. For a number of years, the Wagner Free Institute in North Philadelphia had been conducting a series of lectures on chemistry and mineralogy. A core group of attendees anxious to expand their knowledge were ripe for such an organization. Two gentlemen named Goodson and Ives established the Philadelphia Mineral Club (PMC, now the Philadelphia Mineralogical Society). Modeled after the New York Mineral Club which was founded in 1887, its objectives were to hold monthly lectures for teaching mineralogy, and to take monthly field trips to collect specimens. Field trips were highly social affairs, drawing both young men and women to participate in an academic pursuit.

One of the favorite field trip locations was Fairmount Park, and the Mineral Club made an annual excursion to the site. In two spots, certain mineral species occurred in abundance and could be collected with little difficulty. In the area where Bell's Mill Road crosses Wissahickon Creek, magnetite in black octagonal crystals were plentiful. They were embedded in a soft gray-green serpentine rock which weathered easily, exposing the crystals.

An even more popular spot was the Devil’s Pool, where Cresheim Creek spills into Wissahickon Creek. This location produced pea-sized almandite garnet crystals, and most noteworthy, staurolite crystals. This metamorphic mineral, uncommon in Pennsylvania, was found here in some abundance. A nearby dike, composed almost completely of bladed anthophyllite in radiating tan crystals, meant that a new collector could recover four distinct species in a small area.

In the same era in which the club was established, there was considerable construction taking place in Germantown. This activity required stone for street curbing as well as building construction. The availability of good dimension stone and experienced stonemasons in Germantown made the use of stone much more financially attractive. A series of quarries, mostly small in scope, opened up in different locations around town, mainly where large rock outcrops were available. As these outcrops were developed through hand-drilling and blasting, new sources of mineral specimens came to light. Several of the more gregarious PMC members kept tabs upon these workings on a regular basis.

Among the most productive from a mineral collecting standpoint were six locations in particular. They were as follows: McCrea's Quarry at Germantown Avenue and Mermaid Lane in Chestnut Hill; Comley's Quarry, along Germantown Avenue east of McCrea's, in Mt. Airy; Penn Street Quarry, near the intersection of Penn Street and Belfield Avenue; the Wayne Junction Quarry, at Roberts and Pulaski Avenues; the Wayne Quarries, on Wayne Avenue, between Wyoming Avenue and Seymour Street; and McKinney's Quarry, West Rittenhouse Street between Wissahickon Creek and Wissahickon Avenue (near the current site of the Alden Park Apartments). Remnants of all but the Penn Street Quarry and the Wayne Junction Quarry can still be seen.

The largest and most productive of the six locations, from both a business and mineral collectors' perspective, was McKinney's Quarry. It was also the oldest one, tracing its beginnings to the 1840s, and remaining productive through the turn of the century. It ended a long commercial life trading as the Rittenhouse Quarry. McKinney's was noted for producing an excellent curbstone; it was also a favorite of mineral collectors for its production of large (up to a foot in length) apatite crystals.

McKinney's Quarry developed into a multi-level hillside operation that presented the appearance of a large commercial enterprise. The compact, gray-black gneiss recovered from the quarry lent itself to the efficient shaping of large curbstones. Its location, possibly astride a large pegmatite swarm, made it a rich host environment for mineral specimens.

Another unusual mineral found in the Germantown area was a brownish mica which occurred in large attractive masses. This mineral, also a derivative of pegmatite, was found in some abundance at the Wayne Junction Quarry, and the Wayne Quarries on Wayne Avenue. Local mineralogists named this new species "philadelphite," and under this designation, specimens made their way to collections around the United States. Only later, when more analytical work was conducted, was it recognized that the identification was inaccurate. The mineral was an odd form of the established species vermiculite. Nevertheless, many specimens yet remain in historic collections, and the name "philadelphite" has been retained for nostalgic reasons. Specimens of this local mineral were collected by the author, at the high wall of the Wayne Quarries, as recently as spring 2002.

The Wagner Free Institute and Sam Gordon

About 1915, Dr. Edgar T. Wherry, a young professor of chemistry and mineralogy took up his new teaching duties at the University of Pennsylvania. He moved into affordable housing in North Philadelphia, and soon volunteered to teach young students at the nearby Wagner Free Institute. The Institute had been established in 1885 by industrialist William Wagner, and mandated to teach science and natural history to poor youth unable to pay for their education. The Institute, constructed in the style of European lyceums, featured a three-story building with an open center atrium and glass ceiling. This arrangement allowed a skylight which permitted natural lighting for a large museum that had been added to the facility. The museum was coupled with a large library and class rooms, and all collectively provided an attractive academic environment for young people.

Wherry's chemistry and mineralogy courses quickly drew a number of avid devotees. Among them was a Jewish youth named Samuel G. Gordon. The young man came from a poor area of North Philadelphia. Wherry recognized that Gordon had great intellectual potential, and took special interest in encouraging his student. The surroundings of the Wagner Free Institute exerted a powerful influence on Sam Gordon and possibly represented an avenue of escape from a mundane existence. Mineral specimens in the Wagner museum were of particular interest, and Wherry inspired Gordon to build on this interest through attendance at the Philadelphia Mineral Club meetings. It was here, in the halls of the Academy of Natural Sciences, that the seed of desire germinated in the budding young mineralogist. He would, in the course of the next few decades, develop into a professional mineralogist with an international reputation.

With Wherry's encouragement, Gordon applied for and won a Jessup Scholarship. This award offered employment at the Academy for young men and women of unusual talent. Gordon was assigned to the mineralogy department, working under the tutelage of Curator Frank J. Keeley. Almost immediately, Gordon made plans to write a new publication on the mineralogy of Pennsylvania. An earlier work, written in 1875, was long out of date. Drawing on an earlier series of magazine articles authored by Wherry, Gordon began his compilation in the Philadelphia area."

It was precisely at this time that Wherry had undertaken research on a newly discovered phenomenon known as radioactivity. His interest in this amazing natural energy source, discovered to be generated from the decay of uranium atoms, led him to begin the search for radioactive minerals. These were known to be formed in igneous rocks, and the pegmatite swarms in the Germantown area were plausible locations for discovery. Gordon's need for updated information, coupled with Wherry's desire for radioactive specimens, proved to be an area of mutual interest. These two men, along with a cadre of eager new collectors, began an extensive search throughout the entire Philadelphia area. The desire of this new breed of collector, coupled with the commercial development taking place in the Philadelphia suburbs, led to a period of discovery which reached its climax between 1890 and 1920. It was in the pegmatites at Comley's and McCrea's Quarries that Wherry and Gordon discovered excellent specimens of the uranium minerals autunite and torbernite. The former was found in bright yellow coatings and the latter in bright green crystal flakes. In those early decades of the 20th century, a full understanding of the power of radioactivity had not yet been achieved. In light of our current knowledge, it can be stated with certainty that the abundance and concentration of these unique minerals was too limited to pose any health risk from radon.

In 1922, the young but emerging Samuel Gordon published the results of his locality search. Though Gordon would write more than fifty papers and books in his career, his Mineralogy of Pennsylvania was his magnum opus. Long out of print, it remains a highly sought collectible. At least twenty-five sites in Fairmount Park, Chestnut Hill, Mt. Airy, and Germantown were included in the text, providing a permanent record of many locations lost to urbanization. Gordon would go on to fame as a leading American mineralogist, visiting important locations in Africa, South America, and Greenland. As a curator at the Academy of Natural Sciences, he single-handedly built the collection to world-class status. Gordon also discovered six new mineral species. He named one of them wherryite in honor of his mentor. He himself was similarly honored through the naming of the species gordonite, a new mineral found in Utah in 1935.

In the 1920s, Edgar Wherry was appointed the first crystallographer for the U.S. Government. His work in analytical chemistry, radioactivity, and crystal structure destined him for other important scientific contributions. Wherry lived a long life, and in his mid-thirties, developed a whole new interest in the field of botany. Through the 1940s and 1950s, Wherry was acknowledged as the world's leading authority on ferns. Several species have been named in his honor. Other mineralogists who gained their start in the early days of the Philadelphia Mineral Club, also went on to significant achievements in the scientific world. All would recall with fondness the pleasant hours spent mineralizing in the environs of Germantown and the Wissahickon Valley.