Dravite: A Variety of Tourmaline

This article was published in the November issue of Wayne County Gem and Mineral Club News.  Ninety-one dravites from the WCGMC collection were used to wish the members Happy Halloween.

Dravite is a tourmaline within the Alkali Subgroup 1. This means that the X-site in the complex formula below is predominantly occupied by sodium (Na). In the case of dravite the Y site is occupied by magnesium (Mg) and the Z site is aluminum (Al). The boron cyclosilicate mineral is always dark in color, ranging from chocolate brown to almost jet black. Occasionally, there is sufficient chromium in the Y and/or Z site to impart a dark green color. Dravite is most commonly found in metamorphosed limestones and in higher grade mafic schists.

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Dolomite Gets No Respect

In mid-October, over 130 mineral collectors from several northeast states and Canada converged on Walworth Quarry in upstate New York for the annual fluorite hunt.  Every May, the same crowd treks to Penfield, NY when The Dolomite Group opens that quarry to folks hoping to score a nice transparent-purple fluorite or maybe some dogtooth calcite.  Closer to Buffalo the prized finds are dogtooth calcite, clear selenite, and, of course, small purple fluorites when clubs visit the Lockport Quarry.

Granted the fluorite and other less common vug filling minerals like sphalerite, celestine, and honey colored dogtooth calcite are nice finds and worthy of special attention.  But, there is another fine crystalline mineral hiding in the vugs of the Lockport dolostone.  Yes, I speak of the carbonate mineral, dolomite, or CaMg(CO3)2  Everyone shines their flashlight into the dark vugs of car-sized boulders hoping to see a flat transparent cubic cornered, multi-inch fluorite gleaming back at them.  Absent that observation, collectors move on to the next vug, the next boulder, the next quarry face.

In the next few paragraphs, I am going to try to convince you to take a second look into the vug.  Pause a few seconds to evaluate the white to pink dolomite crystals that you are categorically dismissing as unworthy of your collecting attention.  Are not most of the vugs lined with clean shiny dolomite crystals?  Is there a floater piece in the vug that can be easily removed that displays multiple tiers of brilliantly terminated rhombohedral dolomite?  If yes, just why are these not worthy of extraction?

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Obscure, Bizarre, and Defunct Countries

Over the course of the past couple decades, RPA Club member Steve Eisinger has assembled a rather interesting collection.  He collects stamps together with coins from tiny countries and enclaves around the world.  He keeps the stamps and coins together and organized geographically.  In October, Steve shared his collection with us with a presentation entitled “Confusing, Obscure, Bizarre, and Defunct Countries – Their Coins and Stamps”.

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Maclurites in Plattsburgh

The New York State Geological Association (NYSGA) held its annual meeting in Plattsburgh in September.  The event, hosted by SUNY-Plattsburgh, featured field trips to several Adirondack sites and I attended one on both days of the event.  But we will leave that to a subsequent post.  This note focuses on an outcrop just outside Plattsburgh where the gastropod Maclurites magnus can be found.  Encouraged to visit the site by a SUNY-Plattsburgh geology student, I found time Tuesday September 15th to spend a couple hours walking the outcrop with New York Paleontology Society Field Trip Leader Ray McKinney, who just so happens to live in Plattsburgh.  Meeting him on this trip was an unexpected bonus to attending NYSGA.

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