New England Pegmatites
They Have Been Mined Since America's Earliest Days
by Bob Jones, Senior Editor Rock&Gem Magazine
When the settlers came to the New World, they sought many things, including mineral wealth. They found small amounts of silver and lead, as well as sufficient iron, carbonate and oxide ores to develop the earliest American iron industry. And they found isinglass, which we know today as mica.
In Colonial days, windows were hard to come by. The early settlers often greased paper and used it on window openings. The price of glass was outrageously high, as it had to be shipped to New England from England. In fact, the law required that all manufactured goods had to be imported. Consequently, when mica was found in large transparent sheets that could be split thin and used as strong clear window material, the discoverer was pleased, but fearful.
The earliest extraction of mica was from a pegmatite deposit, now called the Ruggles Mine, in Grafton, New Hampshire. Mica was mined there starting in 1803. The farmer who mined it was so secretive, that he smuggled it into Boston where it was sold as imported goods. The threat of arrest hung over his head, as his raw material was not being sent to England to be made into a finished product.
Shown at left, America's historically famous necklace, the Hamlin necklace in the Harvard collection. The gem tourmalines are from the famous Hamlin 1820 find on Mount
Mica, Maine, starting America's Gem Industry. Photo by Bob Jones.
The Ruggles Mine is just one of hundreds of pegmatite deposits in New England, many of which yielded useful mica. Pegmatites are granite-like intrusives but are distinguished from granite because the minerals which make up the pegmatite are hugely crystallized, sometimes many feet long. A pegmatite is made largely of feldspar, quartz and accessory minerals that commonly include mica.
Feldspar mining started in Connecticut around 1825. From that time on, the pegmatites gradually increased in importance, first for industrial minerals and later as a major source of gem crystals in early America.
By today's standards, the New England deposits, save for some in Maine, would today rank rather low on the excitement scale, especially when compared to the San Diego County pegmatites of California, the prolific pegmatites in Brazil and the very recent finds of pegmatite gem minerals in Afghanistan and Pakistan. Still, the New England deposits were very important in their day, and not just as gem or industrial mineral deposits. Mineralogically, they were major sources of important new species described in the early texts by experts from Yale, Harvard and other institutions.
Today, the Ruggles Mine is just one of hundreds of pegmatite mines, prospects and outcrops found throughout New England. Unfortunately, save for a few locations like the Ruggles, most of the other sites have been either mined out or closed for safety reasons. The Ruggles achieved some fame this century as a source of rare phosphate minerals, many of which were found in micro crystals only. It was also one of the earliest New England mines to be opened on a fee basis for collectors.
Though an important source of industrial minerals like mica and feldspar, New England's pegmatites are best known as America's early source of gems, with tourmaline and beryl leading the way. During World War II, many mines were re-opened for industrial beryl, a strategic mineral. Yet, even then, the production of gems continued.
Shown at right is a rare assortment of tourmalines from one of Connecticut's earliest gem pegmatites, the noted Gillette Quarry, East Haddam. From the New York Museum of Natural History. Photo by Bob Jones
The pegmatite deposits are largely concentrated in five major areas, with several lesser occurrences of note. In Connecticut, the major deposits are centered around the Middletown District, early source of pure feldspar. The Bon Ami Company, for example, mined the Hale Quarry for feldspar abrasive for decades. Major gem mines in the Middletown District include the Gillette and the Strickland mines.
To the west of the Middletown District, near the New York border, are the Branchville Quarry in the town of the same name and the Roebling Mine in New Milford. Both produced fine gems in modest quantities. Branchville is mineralogically important as the source of no less than nine new minerals, including dickinsonite, fairfieldite and other manganese phosphates. The Roebling Mine was operated after World War II as a source of uranium minerals, but it is best known for its fine heliodor crystals mined earlier. Mica was also mined as a commercial by-product, a circumstance true of many pegmatites throughout the New England area.
There are no extensive pegmatite districts in Vermont or Massachusetts. New Hampshire, however, is rich in pegmatites, with the Keene and Grafton districts being most important. There are also several minor districts close to the border between New Hampshire and Maine.
New Hampshire has produced wonderful examples of pegmatite minerals, with topaz leading the way. Superb colorless to blue crystals up to several inches have been found here, some having come from what are called myarolitic cavities in the granite. These are generally small vugs in which rare volatile solutions have collected and formed crystal-lined pockets, primarily containing wonderful smoky and amethyst quartz, with the two colors being seen in one crystal, fine feldspar crystals and superb topaz crystals.
Maine boasts two huge and gemologically important pegmatite districts the Topsham District near the coast and the Paris-Rumford District in the west-central part of the state.
The first tourmalines of gem quality found in America came from near Paris, Maine, when two boys, Elijah Hamlin and Ezekial Holmes, stumbled onto gemmy green crystals scattered by weathering in the detritus of a hillside. This source was developed as the Mount Mica Mine and was a major producer of gems for years.
Shown at right are slices of the Dunton Pit, Newry, Maine find, the last major gem tourmaline discovery in Maine. Photo by Bob Jones.
Maine's last great contribution of gem tourmaline was from the Dunton Pit or Quarry when, in 1972, hundreds of pounds of watermelon tourmalines were found. Most of this was carving-grade material, but hundreds of superb gemmy stones were also cut. The Dunton pegmatite is one of several on Newry Hill, part of Plumbago Mountain in Newry, Oxford County. The find made here was quite unexpected, as the general feeling was that New England pegmatites had seen the last of their halcyon days. This vast and rich find served as an impetus to further pegmatite mining both in Maine and elsewhere.
Shown at left is a slice from the Jolly Green Giant, the watermelon tourmaline Frank Perham dug at the Newry, Maine Dunton Pit. The green rind is richer in iron while the red interior has a greater amount of manganese ions to give it a different color. Smithsonian collection, photo by Bob Jones.
The find at the Dunton dig was spectacular. Perhaps the best-known single crystal to come to light at that dig was later called the Jolly Green Giant, a watermelon tourmaline with a red center and a green "rind." It measures some 3 inches in diameter, and when I saw it, the length was approaching 10 inches. Parts of it were sliced off, but the major portion of the crystal is preserved in our national museum, the Smithsonian Institution.
An exceptional specimen for New England, this crystal was dug by Frank Perham, who has long been associated with Maine's pegmatites. Frank probably knows as much about Maine's gem mines as anyone, and the Perham shop is always a source of good talk and fine gems.
Frank often tells about being in the gem pocket and how he dug into the soft clay-filled pocket before the tip of a green tourmaline appeared. Using a screwdriver (how many times have you been told not to use a screwdriver for mineral collecting?), Frank started to scrape away the enclosing clay. The green crystal was heavily striated and had lovely pyramidal faces forming the termination. As Frank scraped, the crystal kept getting longer and longer, until an almost log-like form emerged. The crystal was not attached to the wall of the pocket, typical of pegmatite tourmalines.
Several explanations have been suggested for the fact that many pegmatite pockets contain crystals broken from where they formed on the walls of the pocket. Ground movement or frost are possible explanations. I like the pocket-eruption theory, wherein the pocket, as it forms, finds extremely high-temperature solutions being concentrated more and more, heated more and more until the remains of the original solution simply flash or explode into steam. Such an event would severely disrupt the pocket contents.
Shown at right is the Jolly Green Giant with one of its slices, now in the Smithsonian. Photo by Bob Jones.
As Frank slowly freed the Jolly Green Giant from its enclosing clay, he began to hyperventilate. He had dug hundreds of crystals in Maine, but none like this monster. He had to rest every so often to absorb the wonder of it all. Finally, the giant gem was free and he was able to bring it up out of the hole. No one could believe what they were seeing. Frank later told his story on the video Gemstones of America as he sat in an open pegmatite quarry on Mount Mica.
Another great find in a Maine pegmatite came about because of the naivete and enthusiasm of a young New Jersey collector, Terry Szenics. Terry is now a well-known mineral dealer/collector based in South America, where he recently discovered a rare hydrous copper molybdenum mineral now named szenicsite.
Terry's big discovery came in 1966, when he determined he was going to find some superb purple fluorapatites in the Pulsifer Quarry at Mount Apatite. Terry had long admired the famous Roebling purple fluorapatite in the Smithsonian Collection that had come from the Pulsifer in the early part of this century. Enamored of this beautiful violet-colored crystal measuring 1-1/2 inches by 1-3/4 inches, Terry determined to attack the Pulsifer pegmatite and replicate the find. He rented some heavy equipment and dug away. In 1966, using heavy equipment just to mine crystals was virtually unknown. People thought him a bit odd, to say the least. But he was a man on a mission!
The results of his risky venture were beyond his expectations, as he mined into the finest pocket of violet fluorapatites to be found at the Pulsifer in decades. Some think his find was the best ever made there. Lovely transparent hexagonal crystals to an inch or more came to light, many on matrix. I recall a New Jersey show some months after Terry's find when he showed me a cigar box full of doubly terminated purple crystals, many an inch thick and approaching 2 inches in length. He had really made a wonderful find, once again proving that Maine pegmatites hold many surprises!
I was never that lucky when working the New England pegmatites. In the early days of my collecting, I was interested mainly in fluorescent minerals. Most localities at that time were either open to collecting or accessible because they were abandoned. When it came time to work on my master's thesis in science, I decided to follow my hobby interest. Armed with a portable long/shortwave ultraviolet lamp, I spent night after night visiting quarries and outcrops all over the state of Connecticut in search of fluorescent minerals. I didn't make any spectacular finds, but did come across lots of interesting things.
One night in the Hale Quarry, I found a spectacular fluorescent area on the wall of the quarry, brilliant blue under both long- and shortwave. It looked like scheelite, but scheelite isn't blue under longwave light and it's a mineral not usually associated with pegmatites. I dug and dug in the dim light of my lamp, getting several masses of the bright rock. Once home, I cleaned my find and it turned out to be a bust. It was drilling oil that had soaked into the feldspar, lighting it up like a blue beacon for my lamp.
All was not lost, however. I did obtain my master's degree and my thesis. The Luminescent Minerals of Connecticut was later published commercially. While the Connecticut pegmatites did not yield lots of fine specimens to me, they gave me something more important!
Probably the most unusual pegmatite mineral I ever collected from a Connecticut pegmatite was pollucite from what was then called the Gotta-Walden Prospect. The Gotta-Walden Farm was close to the famous Strickland Quarry, across the Connecticut River from Middletown in Portland. During an excavation for a farm building, a pegmatite outcrop on the farm was breached and masses of an unusual greasy-looking translucent material came to light among the feldspar and quartz masses. It looked rather like a bubbly wax material. This was later identified as pollucite, a very rare hydrous cesium, sodium, aluminum silicate in the zeolite family. Zeolite minerals are commonly found in small amounts in pegmatites where they form in the last stages of mineralization.
What excited me about this pollucite was that it fluoresced an almost eerie soft green under shortwave ultraviolet light. To top it off, the material could be faceted. Remarkably, even though it is a zeolite, it has a hardness of around 6.5 to 7 on the Mohs scale. Local collectors did their best to obtain specimens of this rare mineral when it was coming from the Gotta-Walden Prospect. Mining commenced, but the deposit never proved to be anything more than a novelty. Still, the fact that it yielded important amounts of a rare mineral made it a noteworthy deposit. Today, huge crystals of pollucite are being found in the pegmatites of Pakistan, the largest being a foot-high complete crystal owned by dealer Herb Obodda.
Shown at right is a fluorite from the Wise Mine, an old New England locality at Westmoreland, New Hampshire. Photo by Bill Welsh.
Collecting isn't all that easy in the East anymore. The pegmatites that were once famous and were studied diligently by scientists from Yale, Harvard and other institutions are now closed or have been swallowed up by progress. Yet, there is the occasional exception. Several of the Maine pegmatites, such as at Mount Mica and the Dunton Pit, have been worked in recent years with success by contract miners. The Wise Mine, a source of fantastic gem green fluorite, is being contract-mined. The famous Palermo Mine in New Hampshire, a Mecca for rare-species micromounters, is still open on a fee/tour basis.
The best bet for collecting is to be a member of a recognized club which can make special arrangements to enter working properties under tight safety regulations. This, at least, does bring to light the occasional fine specimen, while providing collectors with an opportunity to exercise their hobby.
Maine tourmaline also provides fine carving grade material for artists the world over, this from Idar-Oberstein. Photo by Bob Jones.
Though collecting is severely limited today, there are many superb collections in museums and institutions to see. Some of America's most historically important specimens may be seen at Harvard, Amherst, Yale, and the major museums in New York, Philadelphia, Washington and elsewhere. So when you attend an East Coast show or visit the area, be sure to immerse yourself in the historical wealth of minerals to be seen there.
Table of Contents