Sunday, January 20, 2013

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.

Monday, January 7, 2013

Maryland Minerals: S to Z

This is the  fourth and final part of our compendium for the Maryland Minerals website seeking to list all mineral species and varieties of species known to have occurred in Maryland. As in the previous three portions of that compenium, the name of any major mineral family and/or group to which a species or variety belongs appears in parenthesis next to the species/variety name. Duly noted on the list also are a relatively few questionable or unverified occurrences. Also included and similarly noted are the names of species that the I.M.A. has since discredited. Images of Maryland-collected specimens arranged by county for many of these species can be viewed at the website's Maryland-collected minerals slideshow.

For nearly all of information in this compendium, we are grateful to the following sources:

Minerals of Maryland by Charles Ostrander and Walter E. Price, Jr., Natural History Society of Maryland, 1940
Minerals of the Washington, D.C. Area by Lawrence R. Bernstein, Maryland Geological Survey, 1980
Smithsonian National Museum of Natural History Database.

Continuing through the end of the alphabet, subsequent posts will cover the names of additional minerals that have been collected in Maryland.

Saponite  ?
Scapolite (member of Scapolite Group)
Selenite (see Gypsum)
Sericite (synonym for mucscovite)
Siegenite (member Linnaeite Group)
Smagardite (var. Actinolite, a member of Amphibole Group)
Soapstone (see Talc)
Spessartine (Garnet Group)
Sphene (synonym of Titanite, a member of Titanite Group) Spinel (Member of Spinel Group)
Stibiconite (Member of Romeite Group)
Stilbite (Member of Zeolite Group)
Strunzite (Member of Strunzite Group)
Succinite (synonym for Amber)
Tantalite (Discredited by IMA, see Columbite)
Tetradymite (Member of Tetradymite Group)
Thulite (var. of Zoisite)
Thuringite  (a ferroan varitey of Chamosite)
Titanite (a member of Titanite Group)
Tourmaline (synonymous with Tourmaline Group)
Tremolite (Member of Tremolite-Actinolite Series within Amphibole Group)
Turgite (a mixture of Goethite and Hematite-rejected by IMA)
Uraninite (?)
Vermiculite (Alteration product of Mica that's a member of  Montmorillonite-Vermiculite Group)
Wad (Generic name for various manganese Oxides)
Wernerite (a variety of Scapolite)
Williamsite (a variety of Antigorite a member of Serpentine Group)
Withamite (a variety of Epidote)
Wollastonite (a member of Wollastonite Group)
Wurtzite (Member of Wurtzite Group)
Xonotlite (Member of Xonotlite Group)
Zeolite Family
Zinnwaldite (Member of Mica Group)