Friday, January 6, 2012

An Humongous Maryland-Collected Ruby Corundum

Weighing 16 pounds, and measuring 8 1/2 inches x 6 inches x 5 inches and pictured above is the most spectacular and amazing Maryland collected mineral specimen of thousands upon which I have gazed. Shortly after a 2009 visit to the Maryland Geological Survey's Baltimore headquarters on St. Paul St. to view its Maryland minerals on display, my friend Jeff Nagy inquired if I'd seen a gigantic Maryland corundum rumored to be there. Absolutely not: To the best of my knowledge, no Maryland-collected corundum specimens were known to exist.

Two and a half years later, Jeff called and invited me to accompany him to the MGS building for a visit with geologist Bob Conkwright, Jr., MGS Program Chief for Coastal and Environmental Geosciences. It turned out that for many years, this amazing specimen had served as a cherished doorstop in Bob's office.

Bob collected it circa 1960 at age eleven in the company of his father while collecting at one of the three long abandoned Devries Quarries in Carroll County. Once mined for feldspar, two of the Devries openings sit adjacent to each other along a bluff overlooking the Patapsco River near Hentryton. Bob explained:

"Start at the Henryton Tunnel and head downstream. The area was not as wooded back then, and there were just piles of dumps. I saw the weathered end of this thing sticking up and kicked it, hurting my toe. After a little digging, I first suspected it was some kind of hexagonal quartz cross-section."

About a week after our visit with Bob, my friend Harold Levey joined me on a short hike heading north up the railroad tracks along the Patapsco from Marriottsville looking across the river for a spot that could be where Bob made his find. Sure enough, about a hundred yards downstream from the Henryton Tunnel, the two openings remained. Although a few pegmatite rocks were visible on the ground, any dumps that may once have existed had long succumbed to fluvial forces and/or been buried with soil as the area has become heavily wooded. Even so, a few pegmatite rocks were visible. Now part of Patapsco State Park, prohibitions against collecting are actively enforced with inordinately costly penalties.

Open to question is whether this amazing piece was actually quarried from one of the openings upon whose quite shallow dumps Bob collected it. Could it have been loose in the soil/ saprolite layer, or even a product of blasting for construction of the Henryton Tunnel near the turn of the 20th Century? Bob Conkwright is eminently qualified to tackle these questions and has agreed to commit his thoughts to writing for an upcoming sequel to this post.

What is clear, however, is that this unique find from a half century ago makes a strong case that additional corundum is somewhere about. And fortunately, there's no law against checking out the various ever-changing alluvial deposits in and along the Patapsco as it heads downstream.

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