Sunday, January 3, 2016

Bounty of Baltimore County's Texas Quarry

Look  to the right heading north on I-83 between Padonia and Warren Roads. Where not obscured by embankment, you glimpse the enormous Texas Quarry. As one of five Maryland aggregate quarries that Bluegrass Materials purchased in 2014 from LaFarge North America, this ever growing pit has yielded dolostone for various purposes since well before the Civil War. Its length extends for a mile in places, and it penetrates the Cockeysville Marble formation to a depth of more than 500 feet, well below sea level. Over time, it has yielded a range of mineralogically interesting material, most that was collected decades ago ,
Arguably, the Texas Quarry is best known for its dravite, a tourmaline species, which occurs as adamantine crystals in white dolomite and calcite. The above specimen is from the collection of John S. White, past Curator-in-Charge of the Gem and Mineral Collection at the Smithsonian.
Despite its place in the Mica Group, phlogopite can visually resemble dravite. Sharing similar color and adamantine luster,  phlogopite is ubiquitous at the Texas Quarry. The above pictured piece could be the most collection-worthy Texas Quarry phlogopite piece  known to exist. It is a true Maryland classic that was pictured in  Ostrander and Price's Minerals of Maryland (Natural History Society of Maryland, 1940), and is currently owned by Baltimore area collector Bob Eberle.
Scapolite Group species and varieties, often simply labeled as wernerite, have always been a special find. Regardless of nomenclature, if the color is lilac, it's  a Texas Quarry treasure. We acquired the above pictured specimen from the late Baltimore County dealer and collector Larry Krause. The historic Natural History Society of Maryland label that accompanied it noted that it was collected by the late Charles Ostrander, co-author of the aformentioned book.
Never plentiful, most Texas Quarry Scapolite Group material featured greenish gray crystals. This 4.3 cm. crystal is a fine example. Particularly impressive is the pinkish lavender fluorescence of the accompanying calcite.

Relatively little Texas Quarry calcite fluoresces..As attractive as the above specimen appears, we've observed little  to be as  collection worthy as crystals from other well- known Maryland localities.

Rutile in crystals of more than a few centimeters are rare. The well-known Maryland collector Fred Parker collected this 1.6 cm. long crystal in the 1990's
Neither sphalerite nor baryte are particularly common here.  However, they are  notable when associated with each other as shown above along with some dolomite in the mix.
Little if anything relating to the occurrence of  bornite is in any of the literature we've been able to access. Nor has there been mention of chalcopyrite. That Fred Parker's sharp eye spotted this bornite specimen does not surprise us. We managed within a few seconds to observe chalcopyrite in dolostone boulders piled up near the Bluegrass Texas Quarry sign when shooting our title picture.  
The chalcedony in calcite, as pictured above proved to be eminently collectible.
We saved the image of Texas Quarry  pargasite for last.  Another Fred Parker find, it is the only example of this species of which we are aware from  the Texas Quarry or any other locality in Maryland, except for the Hunting Hill Quarry in Montgomery County.

Other species known to occur at the Texas Quarry are as follows :pyrite, tremolite, pink dolomite, wollastonite, fuchsite, purple fluorite, dendrites (probably manganese oxide), galena, pyrrhotite, quartz, sphene, talc, chlorite, molybdenite, margarite, diopside, and asbestos.


Before posting  we contacted Fred Parker in New Mexico to conifrm that he had not only provided but  personally field collected the pictured bornite, rutile, and pargasite as noted.. After confirming this, he shared two facinating remembrances
  • A specimen from a find circa 1935 labeled "sphalerite on limestone." 

Associated with dolomite crystals,they are stacked hexagaonal plates that appear to be sphalerite. I believe these are sphalerite after wurtzite paramorphs and good ones at that. Fred recalled  where this specimen was housed when he observed it. If still in the same collection and access can be arranged, we'll cover it in a subsequent post. 


I also recall in the early-mid 1990's a blast in which a boulder at the base of the rubble pile contained the best dravites I ever saw from Texas, as I recall 3 to 4 inch crystals. They could not be safely recovered so went to the crusher. 

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