Thursday, October 12, 2017

Amazing Hematite Find in Baltimore County, Maryland

This 8 x 7 x 3.5 inch specimen 9 poun specimenfeaturing bladed hematite crystals on chlorite schist from Baltimore County could well be the most intriguing Maryland-collected mineral to show up in the last decade. During the recent Gemcutters Guild of Baltimore's Atlantic Coast Gem, Mineral, and Jewelry show at the Howard County Fairgrounds, it was on display for all to see in a cabinet of about a dozen other specimens that Gemcutters long time member and show-organizer Bernie Emery had self-collected. Notwithstanding, it seemed that but a few of the numerous local mineral aficionados who were there manged to combine the levels of  detailed attention and specialized knowledge to realize the significance of what they were seeing.

It's a find that's almost impossible to believe as well as to refute. Though hematite is the world's primary ore for producing iron and is common in Maryland, it accounted for very little of  the production that thrived here into the early part of the last century. Instead, goethite, magnetite, and siderite  were the principal ores, except on the Coastal Plain where "bog ore" was prevalent.  Maryland's hematite occurs in either rough grainy dark red/black masses or as specular hematite, known also as"specularite." The latter appears as silvery flakes and/or microscopic tabular crystals. Hematite with the appearance of Bernie's recent find is all but unknown in Maryland. After 10 years writing and photographing Maryland-collected minerals and assuming sole responsibility for the Maryland Minerals website, this writer has never seen or heard of another such specimen.

The specific Baltimore County location where Bernie Emery found the specimen is especially curious. He surface-collected it at one of several pits worked for iron over a century ago. They all are a short distance from the NCR Trail near the former Blue Mount Station in Baltimore County. Records show the  ore source to have been exclusively magnetite.  Various publications that describe the mineralogy of the immediate area as well as its specific iron pits and prospects name a variety of minerals. They include tourmaline, apatite, garnet, actinolite, and hornblende. There is no mention of hematite or any other species worthy of mining. The country rock varies from serpentinite to chlorite schist.

Few if any collectors in the region could be more deserving of such a find than Bernie. Over more than three decades, he has been one of its most prolific and best known field collectors. Along with his wife Lynne, he has continuously held major leadership roles at all three of the area's pertinent organizations: Baltimore Mineral Society;  Chesapeake Gem and Mineral Society; and  Gemcutters Guild of Baltimore. His renown is enhanced by a penchant for collecting large sized specimens. That practice has prompted many friends and colleagues to refer to such specimens as "Bernie sized." Retirement from his day job several years ago has brought additional time to enjoy his hobbies. More than ever now, he has taken to perusing old maps and literature in a quest to find new spots to look for rocks.  He likes geological maps that hint where mineralization could be likely, and very old ones that mark the locations of   former and usually long forgotten (and all too often reclaimed or built over) mines and quarries.

After explaining the nature of his research, Bernie explains how the find happened:
I was walking up what appeared to be a  dump pile leading to a small pit that was full of water. On the pile, all the rocks were a rough chlorite schist  with a few small garnets. I noticed this one boulder that was covered with dirt and was curious what was inside it. I tapped off a piece with my hammer. The chlorite schist  was highly metamorphosed  with microscopic magnetitie crystals. I dismissed it and kept walking. 
Except for curiosity, Bernie offered no explanation as to why he returned a few seconds later.
I went back, turned it over. and saw pods filled with the dirt  this boulder had been in for 150 years. The pods appeared to be some other kind of material. There were no blade shapes  (as would suggest hematite). I used a stick to remove some of the dirt and got the impression it was some kind of honeycomb quartz or chalcedony. Further cleaning, I realized they were actually hematite blades that were completely rusted. I showed it to Bob Eberle who offered to clean it further. 
Eberle whose prowess at field collecting is legendary,  had  access to a glass head sand blaster. He took the specimen home and cleaned it up to reveal what he refrred to as "this amazing surprise."

And the question remains. How could such a specimen be here?  According to Bernie:
There's no way of knowing, but my guess is that it came from deep down in the pit and that it was put on a cart or a wagon and fell off. There's no way anyone would have left it there. 
He has since returned to the site and searched extensively.  No trace of hematite or any other specimen of interest  turned up.  Bernie's theory makes sense, but it is unlikely that anyone will ever  know for sure.

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