Minerals of the Greenspring Quarry in Baltimore County, Maryland

Since 2006, the 40 acre former Arundel Greenspring Quarry has been the centerpiece of  Quarry Lake at Greenspring, a thriving gated community comprising about 500 condominiums and 100 single family homes served by 335,000 square feet of office,  retail, and restarurant space. The water within fills a hole  from which over the course of more than a century, 350 tons of Cockeysville Marble have been removed. It is the deepest water in Maryland.

Prior to  closing in 1999, the quarry was an occasional destination for field trips by the Baltimore Mineral Society and other groups. It was known as the McMahon Quarry when Charles Ostrander and Walter Price described it in the Natural History Society of Maryland's 1940 publication Minerals of Maryland. They mostly reported species one might expect to find in the Cockeysville Marble.

In later years,  a significant find of pale blue fluorapatite such as shown at left, attracted the attention of  and became prized by  local mineral collectors. Many of them may have been unaware of  material such as  Pennsylvania collectors Joe and Jean Dague uncovered at the quarry during the late 1990's.

While the  Mineral Bliss post of Jan.20, 2012, entitled An Amazing Visit with Pennsylvania's Joe Dague focused on remarkable finds from the Dague's home state, a major purpose of the visit had been to see material they had collected in Maryland.  While there, I  acquired several flats of their Maryland minerals.

Those flats included not only species for which the Greenspring Quarry was known, but plenty more. Somewhere in all that  Cockeysville Marble, the Dagues unearthed some rich pegmatite. The Greenspring Quarry pieces from those flats are pictured below.   We suspect that some of the specimens could WOW not only many in the local mineral collecting community, but perhaps current denizens of Quarry Lake at Greenspring as well.

                                                       BERYL (var.)AQUAMARINE

                                                      GARNET and SCAPOLITE

PYRRHOTITE

SHORL

MUSCOVITE

ALBITE

An Amazing Visit with Pennsylvania's Joe Dague

It was unbeknownst to me that sulfur crystals such as the one pictured above occurred in Pennsylvania.  As a collector who specializes in minerals collected in Maryland, I'm endlessly amazed and fascinated by the far greater bounty of collectible minerals  from our neighboring state to the north.  Of course, Pennsylvania covers a larger area and has a lot more people prone to pursuit of its mineral bounty.

Last month, I had the pleasure of visiting the very accomplished veteran Pennsylvania field collector who unearthed that sulfur crystal at the Jacksonville Quarry in Centre County.  In the company of his his wife Jeanne as well as other prominent Pennsylvania collectors, Joe Dague has been at it for decades.

Although the primary purpose of my visit was to see some of the pieces he had picked up on outings to Maryland a few miles south  from his Chambersburg quarters, Joe's Pennsylvania specimens distracted me.  Not that he didn't have plenty of great Maryland material, which we will be covering on one of two related posts in the coming months.

Since his Maryland minerals were packed away in flats, some of the  first mineral specimens Joe showed me were in a small cabinet bearing thumbnails. Upon its shelves were more interesting and unusual Pennsylvania minerals  than I could even begin to digest.

How about tyorlite from the McCauley Prospect #17 near Franklin Township in Lycoming County, PA?  To my knowledge and according to all that's posted on Mindat, this is the only locality in Pennsylvania from which tyrolite was ever reported. Sometime after that discovery, about 30 years ago, someone bulldozed the McCauley Prospect  dumps back into its pit, which has long grown over.

Another piece that instantly amazed me was a specimen of enargite altering to conichalcite and cornubite shown at right. Joe collected this from the Lime Bluff Quarry near Muncy, also in Lycoming County.

Grabbing me no less was that green sphalerite at left from the Thomasville underground limestone mine Jackson Township in York County. This specimen came from a find in 1990 by the preeminent Pennsylvania field colletor Bryon N. Brookmyer. When Wendell Wilson, Editor-in-Chief and publisher of Mineralogical Record saw these specimens, he proclaimed them the best green sphalerite he'd ever seen.

In addition to all the rare, unusual and regional species he and Jeanne have collected in the field, their worldwide wurtzite suite could be the best anywhere. It's Joe's favorite species. He explains why:

Jeanne and I collected the wurtzite specimen (pictured at right)  about twenty years ago at a coal strip mine in Elk County, Pa.  I'm especially fascinated by the wurtzite mineral species because the marine shales overlying the Brush Creek and Vanport limestones in western Pennsylvania are the type localities for three wurtzite polymorphs--4H, 6H and 15R.  For natives of Western Pa. such as Jeanne and me, wurtzite remains one of the very few interesting minerals that collectors can find in the old abandoned strip-mine in that area.  In addition to several Pennsylvania sites, we now have wurtzite specimens from 17 localities worldwide.

Another Dague specialty is kimberlite, especially Pennsylvania kimberlite, of course. While no Pennsylvania kimberlite is known to bear diamonds, as it does in Arkansas, Pennsylvania is well known for two kimberlite dikes. The first is the Gates-Adah Dike, which is located in an outcrop along the Mongonahela River where Fayette and Greene Counties meet. The other, the Dixonville-Tanoma Dike is beneath the earth in the Tanoma Coal Mine. Pictured below at left is a kimberlite specimen from a THIRD! little known Pennsylvania  kimberlite dike.An image of it appears below at left.  Per Joe,  here's the scoop:

(It's) a rock sample of the third known kimberlite dike in Pennsylvania--the Ernest mine kimberlite. Jeanne and I collected this sample  on August 22, 2009.  Our find of this specimen confirmed its previously suspected existence, and it is now the third known kimberlite dike in western Pennsylvania, and the first to be discovered here in nearly a century.

And that's not all. While my research may not be exhaustive, it's clear that little if anything has been written regarding a kimberlite dike existing  in Maryland. Regardless, Joe showed me and allowed me to photograph for publication here a specimen of Maryland kimberlite. Please stay tuned on this one. It will be the subject of yet another subsequent post in several months.