Wednesday, November 30, 2011

A "New Old" Baltimore County Locality

Call it "new" because there's little evidence that many people know about it. Call it "old" because my friend Harold Levey collected kyanite and staurolite here sixty years ago. The locality is on a hillside with extensive outcrops along the south bank of the Gunpowder River immediately east of the Paper Mill Road Bridge(s).

I can't think of another locality where garnets (var. almandine) are more prevalent than in the biotite muscovite plaglioclase-quartz schist that comprises these outcrops. Closer to industrial than gem quality and often quite weathered, garnets up to about an inch in diameter are everywhere.

Quartz that frequently intrudes into the schist, is what Harold recalls as the most likely matrix for kyanite. Typically bladed, he remembers finding it in loose rocks fetched from the ground. The season had been summer, and those rocks were not so hidden as they were today by a late November canopy of leaves. Otherwise, I suspect we'd have found some kyanite. However, we did come up with some staurolite.

This is probably he same locality that The Natural History Society of Maryland's 1940 publication, Minerals of Maryland , by Charles W. Ostrander and Walter E. Price, referred to as "At Ashland." The only other printed words were "In schist-kyanite, staurolite, and garnets."

We found the staurolite in the same schist that yielded all the garnets. The crystal bore the same almost gemmy luster as the ones Bob Simonoff encountered this past spring near Rockland. The fact that Minerals of Maryland listed no other Maryalnd localities for staurolite would lend further support that this was Ostrander and Price's "Ashland."

Very appealing about the locality is that by all indications, it appears to be collector friendly, so long as not swarmed en masse as a field trip destination, of which it should hardly prove worthy. Currently, parking for one car is available at a small pull-off immediately south of the bridge. When fishing season resumes, the space likely will be taken, or worse a no parking sign could be screwed to a metal post as one probably was at some point in the past. There are two slightly larger places to park not far down the road on the other side of the bridge.

The northern bank of the Gunpowder is similarly rocky. Harold recalls having prospected here as well, albeit to little or no avail.

Sunday, November 13, 2011

Collecting at Sugar Grove, West Virginia

West Virginia? Aside from the meager Sugar Grove road cut locality in Pendleton County, I often wonder what else this state has to offer the mineral collector and why more information is not available. Considering the abundance of localities in all the states that surround West Virginia, such a dearth of mineral localities doesn't seem to add up. And certainly should not some of the geological activity that formed all those mountains left the state with more places to collect?

Pictured above from left to right at Sugar Grove are Robert Miller, Patrick Haynes, Maureen Campeau, and Stephanie Thi, all having a wonderful time breaking open chunks of basalt freed from the the shale into which they intruded millions of years ago. Therein are endless vugs which bear a variety of mineral species that can be quite spectacular when viewed beneath the scope.

Particularly notable is filiform pyrite, one of the most intriguing of this common mineral's numerous morphological forms. Filiform pyrite is has crystallized in the form of needles, which sometimes bend at right angles. Often at Sugar Grove, these needles are associated with the soft iron-rich clay silicate mineral nontronite, which can range in colour here from a light gray-blue to greenish black. At left is an example where the filiform pyrite has threaded dark spheres of nontronite. A right angle bent pyrite crystal coated with light bluish gray nontronite is shown at right. Microscopic pyrite crystals of other habits occur at Sugar Grove as well. Intergrown cubes are particularly prevalent

Chabazite (variety phacolite) is also notable amidst Sugar Grove's bounty. The larger crystals are easily identified. Smaller crystals that are visually quite similar to the phacolite, however are unfamiliar enough to stump me on visual identification. In the image at left, the larger 7mm. crystal to the right is obviously phacolite, but the smaller crystals to the left of it, I'm not so sure about. Included among them could be analcime and harmotome perhaps chabazite of a different habit, possibly even calcite, which is also common in these vugs, occasionally in the largest crystals of any species known to occur here.

Less common, but fun to find, is mesolite. Over three hours of cracking open rocks and peering with my loupe into vugs, the piece shown at right was the only mesolite that I, or to the best of my knowledge, anyone in our group came up with.

Though the collecting was better than expected, the locality was quite different than what I'd expected to find. It is an unremarkable looking road cut on the west side of Sugar Grove Road about 12 miles south of its intersection with Route 33. Needless to say, the area is quite rural. A possible landmark approximately 100 yards to the north on the opposite side of Sugar Grove Road is a couple of sheds, one with open sides, and a possible presence of a few old farming and/or construction vehicles and equipment.