Extracted from Mineral News, Vol. 33 (2017), No. 4
(sans illustrations)


Ferrostrunzite from Marlton, Burlington Co., New Jersey
And Its Relationship to Type Locality for Ferrolaueite

Tony Nikischer
Excalibur Mineral Corporation

After more than forty (40) years of hawking minerals, it is with some skepticism (and often suspicion) that we at Excalibur approach the labeling of specimens. Unanswered questions and mysteries often crop up when trying to confirm old label information, particularly with reference to species identification and locality confirmation that we routinely undertake. Mineral News has published several articles on the general topic of deciphering such mysteries, and the historical searches are part of the joy of resolving label conundrums. Sometimes, we can successfully add one or more new minerals to a known locality, or occasionally document or refine a locality that has slipped away from modern recognition. In publishing those findings, Mineral News satisfies the need to add reliable documentation to the mineralogical literature. The following story is just one more example of how time-consuming such activities can become.

It is routine for us to briefly check Mindat.org and other references before listing material in one of our periodic catalogs. We do this to simply confirm locality spellings, assure ourselves that the particular mineral has been reliably reported from the locality, and perhaps even spot photographs or descriptions of material to compare the overall quality and likely associations of what we are offering to that which has already been collected and documented elsewhere. Easy, no?

Unfortunately, we frequently encounter problems with either the species, the locality, or both, based on the data that has been previously described when compared to what a specimen’s label may indicate. Species identification is not usually a major issue, simply because we have analytical capability in our own laboratory at our warehouse. When our in-house analytical capability doesn’t provide a definitive answer, however, we can ship material elsewhere to other experts that have different analytical techniques at their disposal. The discovery of a number of new species that we have been involved with extends directly from this process.

But what to do when the locality apparently has never been reported or does not exist in any modern reference at our disposal? In some cases, research is required to decipher an old locality name that may have changed due to war, redrawing of political boundaries, or language changes resulting from those factors. Sometimes, the preponderance of evidence suggests a simple misspelling that can easily be corrected, or perhaps a translation from one language to another sheds illumination on the problem. All require some effort, and usually a fair amount of time to properly document. And sometimes, we must surrender and accept a labeled locality for what it is when our efforts are not fully rewarded with an undeniable “truth”.

While rummaging through a previously unopened crate, we uncovered a small box of truly excellent ferrostrunzite specimens from the estate of the late Julius Weber, micromounter and photomicrographer par excellence, (see figure 1). He was active well before the advent of digital cameras and stacking software, and along with Lou Perloff, compiled a remarkable micromount collection, taking many thousands of fine mineral photomicrographs as well in his Mamaroneck, NY home (see Mineral News, (2005) Vol. 21, No. 2 - Editor). The locality on Weber’s label, (Marlton, New Jersey) is absent from Mindat.org, and although similar marl deposits like Mullica Hill and elsewhere are relatively well known among collectors, this one was somewhat of a mystery.

The small community of Marlton (officially part of Evesham Township in Burlington County) was apparently named for the marl that commonly and widely spread throughout the region. Wikipedia states:

The name Marlton first appeared in the early 19th century. The name is derived from marl clay, which is commonly found in the local soil. The discovery of the marl content helped local business and farmers, and caused the first "building boom", occurring in the 1830s and 1840s. Marl continued to be excavated in Marlton until 1930, when the pits were shut down.

In discussion with local experts, it was apparent that Marlton was a legitimate mineral locality, but much confusion still existed about the precise locations of the many phosphates found in the local marl deposits. Chet Lemanski kindly answered my early inquiries by pointing out that the Cretaceous blue marl belt runs from the seashore in Monmouth County (Marlboro localities), through Burlington County, Camden County and Gloucester County to the Delaware River, and then surfaces again in Delaware. Marlton is named after the marl belt and has mineralization similar to the Marlboro, My Creek, Birmingham, Vincentown, Southampton, Hanover, Haddonfield and Mullica Hill localities, as well as several other deposits in the area sometimes seen on old labels. Chet also noted that some of the northern collecting areas in the area were near a rural road that was the junction of a three-county jurisdictional line.

Adding to this confusion was the eventual and much belated publication of the description of ferrolaueite, a new phosphate mineral approved in 1987 but not published until 2012. Before his untimely death, one of the authors (Jim Ferraiolo) kindly provided me with specimens of the new mineral some years ago while the remaining authors wrestled with publication. From the original group of authors, Curt Segeler had died, Paul Moore had left the University of Chicago and was no longer active, and Frank Leans, the primary field collector, had also passed away. Jim died within two years of the final publication. Both ferrolaueite and ferrostrunzite occurred in these samples. The Ferraiolo specimens had been collected by Frank Leans in 1982, and the locality was given as “Hanover Township, Burlington Co., New Jersey”. This was certainly different than the type locality in the final paper that gave the locality as “My Creek”, in Monmouth Co., New Jersey!

Adding still more confusion, specimens of ferrostrunzite in the Excalibur inventory disclosed specimens from several different collections, including some from well known micromounter John Ebner, noted as Location #4 from both Monmouth and Burlington Counties, much like Frank Leans specimens that were labeled as Burlington County! The age of the ferrostrunzite specimens in the inventory suggested the collecting period was likely as early as the late 1970s and up to 1989.

A detailed letter from John Ebner really helped to solve the mystery! In a nutshell, John Ebner’s “Location #4”, as well as Frank Leans’ “My Creek” were on the same muddy creek! More importantly, depending upon which side of the culvert that ran under Province Line Road from which you collected, this would determine whether you were in Burlington Co. (south side of the road) or Monmouth Co. (north side of the road)! Both locations produced identical specimens, simply because they were, in fact, the same muddy creek that meandered through both counties.

It has been nearly 90 years since the marls of Marlton were last harvested on a commercial level, and much has changed in the area since then. The original Evesham Township in which Marlton is located was bounded by tributaries of the Delaware River, the South Branch of the Rancocas Creek on the east side, and Cropwell Creek on the west side. No trace of the marl pits remains today. Careful examination of Julius Weber’s material suggests mineralization similar to other localities along the Cretaceous marl belt and its numerous small creeks, with ferrostrunzite and vivianite apparently the most frequently encountered species. Other species noted on various Weber labels indicate possible strengite, rockbridgeite and/or dufrenite, but these have not been analytically confirmed as yet.

I would like to express my thanks and appreciation to Chet Lemanski and John Ebner, both of whom contributed their time and personal knowledge of the area in responding to my inquiries.