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Friday, June 17, 2011

Gemstone Occurrences in Maine

An example of carving grade tourmaline from the Dunton Quarry strike in Newry Maine.
Photo by Rob Lavinsky

There are many gemstones found in the pegmatites of Oxford County in western Maine including beryl, topaz and tourmaline, Maine’s state gemstone.  This is almost enough to make you cry, one writer describes the destruction of 225,000 carets of chrysoberyl in a blast in a pegmatite near Paris, Maine, the same writer also describes twinned crystals of this mineral weighing up to 120,000 carets that have come from the same locality.

The oldest gem mine in the United States is located on Mt. Mica an LCT Class of pegmatite in Paris the same quarry is also the second oldest known deposit of elbaite in the United States after its initial discovery at the Clarks Ledge Quarry in Chesterfield, Massachusetts. Elbaite is another name for colored tourmaline.  The Mt. Mica deposit has several other firsts including the discovery of the first rose quartz in the world.

Morganite beryl another gemstone found in Maine
Photo by Gery Parent

In the fall of 1972 a monstrous tourmaline pocket was found in the Dunton Quarry of Newry on a spur of Plumbago Mountain.  This pocket is legendary in the annals of gem mining as it yielded more then $8,000,000 worth of gem and specimen quality tourmaline.  The haul was so large the discoverers had to buy an abandoned bank building in Mexico where they stored the gem grade tourmaline in the bank vault and the specimen grade in the basement.

So important are the pegmatites of western Maine that there is a weeklong event held at the Poland Mining Camps called the Maine Pegmatite Workshop every year for the past ten years. In 2011 the workshop started on May 28. Further information about the Pegmatite Workshop can be found on their webpage.

A crystal of clear topaz
Photo by Rob Lavinsky

Tourmaline isn’t the only gemstone found in Maine there are many others.  One of these was the deposits of amethyst that came from Deer Hill in Stow that is now closed to the public.  Here the amethyst came from three quarries the Deer Hill Mine, the Nevel Mine and the Intergalactic (Eastman Ledge) Mine.  The Intergalactic Mining Company is presently mining for blue aquamarine crystals.  Aquamarine is another gemstone that is often found with tourmaline in pegmatites.

Topaz is another gemstone found in Maine with the deposits of Stoneham containing the only sizable crystals in the state.  This is a stone that is often confused with clear quartz, but glistens more when struck by sunlight.  Clear and smoky quartz crystals often accompany topaz in the states many pegmatites.  Transparent smoky quartz is often called smoky topaz or Spanish topaz if it has been heated assuming a yellowish tint.

A Maine amethyst point from Deer Hill in Stow
Photo by Rob Lavinsky

Along the banks of the St. Croix River in Perry one can find agates that have weathered from the basalt flows that are also along the river.  These basalt flows also contain native copper that was observed by the author on a collecting trip to Perry in the 1960s.  Agates are hard to see unless they have been wet by water that really makes them stand out.  The deposit also contains chalcedony and jasper.

An agate like those found at Perry along the St. Croix River
Photo by Hannes Grobe

Jasper can also be found on Jasper Beach in the district of Machias that is called Starboard along the coast right below the radar station.  The beach here is a shingle beach of rhyolite with some jasper mixed with the rhyolite stones.

There have been reports of black jade coming from the river that flows through Farmington.  If this is true it is one of the few reports of jade on the east coast.  The link for the Farmington locality also contains an extensive list of Maine minerals and their localities.

Literally there are hundreds of localities in Maine where gemstones can be found the best advice is to buy a book about the many collecting localities in the state from one of the local rock shops.

1 comment:

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