The Flint Rock and Gem Club is a non-profit organization. Its purpose to promote and encourage the understanding of earth sciences, lapidary arts, and their related fields. Our goal is to share information with club members, educational institutions, and the general public.
Club meetings are held every third Thursday of the month, February through October, at the Clio Senior Center 2136 W. Vienna Road in Clio.
Please note there are no meetings in the months of November, December, and January.
Executive board meeting: 6:00 pm.
General membership meeting: 7:00pm.
Visitors are always welcome.
Membership dues are $10.00 per year, which includes the club newsletter, participation in the annual rock swap, the Flint Rock and Gem Show, club picnic, and annual banquet.
Cabochon classes are on Mondays from 5:30 pm – 8:30 pm. Summer hours 6:00 pm – 9:00 pm will resume on March 15, 2010.
The Flint Rock and Gem Club is a member of Midwest Federation of Mineralogical & Geological Societies.
We’re looking forward to the 2010 season,
opening on Friday March 26th
What is a trilobite?
A trilobite is form of invertebrate marine life that lived more than 500 million years ago, but are now extinct. These hard-shelled prehistoric critters roamed the sea floor and coral reefs in search of food. Because of their great diversity and often perfect preservation in fine-grained rock, they are one of the most popular fossils among collectors.
Are the fossils easy to collect?
The fossils are found in a limestone shale. This shale splits easily into flat sheets, revealing the trilobite fossils. Fossilized trilobites lay nearly flat along the splitting planes of the shale. U-DIG Fossils can provide a hammer or you can bring your own. If you desire to remove your own fresh rock, larger tools are available. There’s little need to do this, though. Fresh chunks of fossil-bearing rock are regularly extracted and exposed from the bedrock with heavy equipment by the U-DIG staff.
How many fossils will I find?
The average visitor finds ten to twenty trilobites in a four-hour period. If you’re having trouble, friendly U-DIG personnel roam the Quarry area and would be glad to show you the richest veins of fossil-bearing rock. They can show you how to split the rock to find trilobites, and can identify what you find.
What does U-DIG provide?
Unlimited trilobites! U-DIG Fossils provides you with forty acresof the best trilobite collecting in the world. We expose fresh rock with an excavator on a regular basis. We can also provide hammers to split the shale, buckets to hold your collection and to carry your fossils to your vehicle in the parking area, digging instructions, assistance in finding and identifying fossils. We also provide toilet facilities.
Best of all, we always provide experienced, friendly staff. Gene Boardman or Bevan Hardy will assist you at the quarry.
When can I visit the U-DIG quarry?
The U-DIG Fossils quarry opens on Friday March 26, 2010.
Business hours are Monday through Saturday from 9 a.m. to 6 p.m.
The quarry is closed on Sundays.
However, the quarry is open on other holidays during the season. In fact, they can be our busiest days!
Please arrive at the quarry before 4 p.m., though. The quarry will close early if no one is present at 4 p.m. Please do not attempt to enter the quarry when it is closed.
How do I get to the quarry?
The U-DIG Fossils Quarry is located approximately 52 miles west of Delta, Utah, near Antelope Springs. It is approximately 90 miles from Provo to Delta. It is approximately 130 miles from Salt Lake City to Delta.
Once in Delta, first travel 32 miles west on Highway 6 / 50. At the Long Ridge Reservoir sign between mile markers 56-57, turn right. There is a U-DIG Fossils sign at this intersection. Then travel 20 miles down a well-maintained gravel road to reach the U-DIG Quarry. Any type of vehicle can travel this gravel road. (To see this route in Google Maps, click here.)
Can we drive an RV to the quarry?
Yes, you can! When you arrive at the quarry, smaller RVs can turn into the Quarry and park in a small parking area to the left, before the “Open” sign. You will then need to walk about 300 yards over to the office for assistance. Larger RVs will need to pull over to the side of he main road just below the “Welcome to U-DIG” sign. Do not pull into the Quarry. Leave your RV there and walk to the Quarry office, about 500 yards. When you are ready to leave, you can continue up the main gravel road, about 1/8 mile, to another connecting road. You can turn around at this location. Examine the Google Maps Satellite view for an overview.
U-DIG Fossils is a family-run business. We’re anxious for you to have a unique and rewarding experience in our quarry. Please call or e-mail if you have any questions. We’d be glad to help. Here’s our office address. (Please note, this is not the location of the Quarry. See above for directions to the Quarry.)
P.O. Box 1113
350 East 300 South
Delta, Utah 84624
(435) 864-4294 FAX
The Messel Pit (German: Grube Messel) is a disused quarry near the village of Messel, (Landkreis Darmstadt-Dieburg, Hesse) about 35 km southeast of Frankfurt am Main, Germany. Bituminous shale was mined there. Because of its plethora of fossils, it has significant geological and scientific importance. After almost becoming a landfill, strong local resistance eventually stopped these plans, and the Messel Pit was declared a UNESCO World Heritage site on 9 December 1995. Significant scientific discoveries are still being made, and the site has become an increasing tourism site as well.
Brown coal, and later oil shale was actively mined from 1859. The pit first became known for its wealth of fossils around 1900, but serious scientific excavation only started around the 1970s, when falling oil prices made the quarry uneconomical. Commercial oil shale mining ceased in 1971, and a cement factory built in the quarry failed the following year. The land was slotted for use as a landfill, but the plans came to nought, and the Hessian state bought the site in 1991 to secure scientific access. In the few years between the end of mining and 1974, when the state started preparing the site for garbage disposal, amateur collectors were allowed to collect fossils. The amateurs developed the “transfer technique” that enabled them to preserve the fine details of small fossils, the method still employed in preserving the fossils today.
Due to the extraordinary fossils, the pit was declared a UNESCO world heritage site in 1995, the only place to be placed on the list exclusively due to fossils.
Many of the known specimens from the site have come from amateur collectors, and in 1996, an amnesty on previously collected fossils was put in effect, in the hope of getting privately owned collections back into public ownership and available to science.
The current surface of the Messel pit is roughly 60 m below the local land and is about 0.7 km² in area. The oil-shale bed originally extended to a depth of 190 m. 47 million years ago in the Eocene when the Messel deposits formed, the area was 10° further south than it is now. The period was very close to the Paleocene–Eocene Thermal Maximum, and the climate and ecology of the site were very different. A large series of lakes, surrounded by lush sub-tropical forests supported an incredible diversity of life. The Messel lake bed was probably a center point for drainage from nearby rivers and creeks.
A fossil of the primitive mammal Kopidodon, showing outline of fur
The pit deposits were formed during the Eocene Epoch of the Paleogene Period about 47 million years ago, based on dating of basalt fragments underlying fossilbearing strata. Oil shale, formed by the slow anoxic deposition of mud and dead vegetation on the lake bed, is the primary rock at the site. Its sediments extend 130 m downward and lie atop an older sandstone foundation. The fossils within the shale show a remarkable clarity and preservation due to the unique depositional characteristics of the lake. The upper stratifications of the lake most certainly supported a variety of organisms, but the bottom was subject to little disturbance by current, spawning a very anoxic environment. This prevented many epifaunal and infaunal species from inhabiting this niche, and thus bioturbation was kept at a minimum. Overturn of the lake layers (caused by seasonal variations) lowered oxygen content near the surface and led to a periodic “die-off” of aquatic species. Combined with a relatively low rate of deposition (0.1 mm/yr), this provided a prime environment for the preservation of fauna and flora.
The Messel Pit provides the best preserved evidence of Geiseltalian flora and fauna so far discovered. Most other sites are lucky to contain partial skeletons, but Messel boasts extensive preservation of structural integrity, even going so far as to preserve the fur, feathers, and “skin shadows” of some species. Unusual preservation has sparked some closely-reasoned interpretations. The symptomatic “dumb-bell”-shaped bite marks on either side of the leaf vein on a fossilised leaf have been identified as the death-grip of a carpenter ant terminally parasitized by a fungus that, apparently then as today, comandeered its behavior, in order to release its spores from a favourable location; it is the earliest concrete sample of fungal behavioural manipulation.
The diversity of species is no less astonishing (thanks in part, perhaps, to the hypothesized periodic gas releases). A brief summary of some of the fossils found at the site follows:
Early primate fossil with anthropoid (i.e. non-lemuroid) characteristics (discovery made public May 2009), (see Darwinius masillae)
Over 10,000 fossilized fish of numerous species
Thousands of aquatic and terrestrial insects, some with distinct coloration still preserved
A plethora of small mammals including pygmy horses, large mice, primates, ground dwellers (hedgehogs, marsupials, pangolins), aardvark relatives, and bats.
Large numbers of birds, particularly predatory species.
Crocodiles, frogs, turtles, salamanders, and other reptiles or amphibians
Remains of over 30 distinct plant species, including palm leaves, fruits, pollen, wood, walnuts, and grapevines
Exhibits from the pit may be seen in the Messel town museum, the Museum of Hessen in Darmstadt (5 km from Messel) and also the Senckenberg Museum in Frankfurt (some 30 km from Messel). Casual visitors can park close to the pit and walk around 300 m to a viewing platform overlooking the pit. Entrance to the pit is only possible as part of a specially organized tour.
An enduring geological mystery. A world-famous mineral deposit. And, it’s all right here in New Jersey, just an hour’s drive from midtown New York!
The industrial complex that was once the Sterling Hill zinc mine is now open to the public as the Sterling Hill Mining Museum. Join us for underground mine tours, fantastic displays of “glow-in-the-dark” fluorescent minerals, extensive outdoor displays of mining machinery, and exhibit halls packed with things you’ve probably never seen before!
Mineral collecting at Sterling Hill (daytime only)
Where: Sterling Hill
Time: 9:00 a.m. – 3:00 p.m.
Description: Collecting allowed on Mine Run dump and in the Fill quarry, Passaic pit, and “Saddle” area Open to the public.
Fees: $5 admission; plus $1.50 for each pound of material taken
Age Requirements: 7-years and up for Mine Run dump; 13 and up elsewhere
September 11, 2010
Fossil Discovery Center
Where: Sterling Hill Mining Museum, Ogdensburg, NJ
SHMM will have a paleontologist available for young people (of all ages) to go fossil hunting. The Fossil Discovery Center is still in a pilot stage, but is based on SHMM’s successful Rock Discovery Center. The “digs” will begin at 10:00 and take place every half hour thereafter; each dig will last a little less than 30 minutes.
Participation is limited to 25 people per session on a first-come, first-serve basis. Each fossil collector will get 6 fossils with a general ID chart.
(Groups of 15 people or more can make an appointment at the Museum Shop to participate in the FDC for other weekends or weekdays, pending availability of SHMM personnel.) Note: 12:30 time slot not recommended for people taking the 1:00 PM mine tour. Other time slots available by appointment for groups of 10 or more.
Age Requirements: All Ages – recommended for students in grades 2 -12
September 25, 2010-September 26, 2010
Franklin Gem and Mineral Show and Outdoor Swap and Sell
Where: Franklin School – Franklin, NJ
Time: 9:00 a.m. – 6:00 p.m.
This show is held the last full weekend in September and features both indoor and outdoor mineral, fossil, and gem dealers.
September 25 (Saturday)
54th Annual Franklin Sterling Gem and Mineral Show and Outdoor Swap/Sel Franklin Middle School, Buckwheat Rd. at Washington St., Franklin, N.J.
9AM – 6PM (indoors); 7:30AM – 6PM (outdoor swap and sell).
Annual Show Banquet and Auction
Franklin Firehouse, Buckwheat Rd. at Parker St., Franklin, NJ.
Banquet begins 6:30PM; tickets $18.
Sterling Hill Garage Sale
Sterling Hill Mining Museum, Christiansen Pavilion, 10AM – 3PM.
September 26 (Sunday)
54th Annual Franklin Sterling Gem and Mineral Show and Outdoor Swap/Sell
Franklin Middle School, Buckwheat Rd. at Washington St., Franklin, NJ
10 AM – 5PM (indoors); 9AM – 5PM (outdoor swap and sell).
Sterling Hill Garage Sale
Sterling Hill Mining Museum, Christiansen Pavilion, 10AM – 3PM.
Mineral collecting at StHMM (daytime only)
Collecting allowed on Mine Run dump and in the Fill quarry, Passaic pit, and “Saddle” area. Open to the public.
Hours 9AM – 3PM. Fees: $5 admission plus $1.50 for each pound of material taken.
Fees: Open to the Public
Age Requirements: Seven years and up for Mine Run dump; 13 and up elsewhere.
Who would think that one of the most famous mines in the world lies right here in the Highlands of New Jersey, just an hour’s drive from midtown New York City?
The Sterling Hill zinc mine is world-class by any standard, and not just because of what was mined here: history was made here, too, lots of it. So too was much money. Moreover, much mining law was forged here, and over the span of two and one-half centuries, this mine and its twin in nearby Franklin dominated the lives of thousands of New Jersey residents. The economic, social, and scientific significance of our local zinc mines was felt not only in Sussex County, but in all of New Jersey and even far beyond.
Consider just these 14 facts:
Sterling Hill is one of the oldest mines in the United States and was first worked sometime before 1739, more than 265 years ago.
Sterling Hill produced more than 11 million tons of zinc ore. The ore was fabulously rich, averaging more than 20% zinc, and occurred in thick seams that were worked to a depth of more than 2,550 ft below the surface through tunnels totaling more than 35 miles in length.
Sterling Hill is one of the world’s premiere mineral localities. Together with the nearby Franklin orebody, 2.5 miles to the north, more than 350 different mineral species have been found here — a world record for such a small area. More than two dozen of these have been found nowhere else on Earth. To view the mineral list click here.
The mine is equally famous for its fluorescent minerals. Together with nearby Franklin, almost 90 different mineral species have been documented as fluorescent (view the list here). Specimens from Franklin and Sterling Hill are widely regarded by collectors as the world’s finest.
Sterling Hill constitutes a geological enigma — other than nearby Franklin, nothing else quite like it exists on Earth. The scientific literature on these deposits spans two centuries and totals more than 1,000 papers, yet scientists have yet to agree on how they formed.
For more than two centuries the Franklin-Sterling Hill district attracted the attention of the most prominent scientists and naturalists of the day. One of the earliest mineralogical papers in U.S. scientific literature (1810) was devoted to zincite, one of the local ore minerals.
Much U.S. mining law was forged in this area as a result of numerous courtroom battles during the 19th century, when mining was done by numerous small companies that often held conflicting titles to the mineral rights. Resolution of these conflicts established legal precedents that governed much of the mining industry nationwide from 1897 onwards.
The town of Ogdensburg owes its very existence to the Sterling Hill mine. For many decades the mine provided employment to local residents and in many ways dominated their lives. Until the 1980s, most of the tax revenue of the Borough of Ogdensburg was linked either directly or indirectly to the Sterling Hill mine, the only large industrial complex in the Borough.
Without the presence of the Sterling Hill mine, rail service to Ogdensburg would have been much delayed. The establishment of rail service in 1871 brought immediate and long-continuing prosperity to the Borough of Ogdensburg by transporting goods for its local merchants, delivering its mail, shuttling its residents on shopping trips and excursions, carrying its public school graduates to neighboring high schools, and providing a means of shipping the local zinc ore to the smelter in ever-increasing quantities.
The continual need for laborers in the mine brought wave after wave of immigrants to the area, including Russians, Hungarians, Poles, Scandinavians, Cornishmen, Mexicans, Irishmen, and others. Pick up an Ogdensburg phone book and look at the surnames, and you’ll see the legacy of those days.
The wealth taken from the hills of Sussex County often had benefits elsewhere. At Princeton University, for example, one of the prime benefactors in the early 20th century was Edgar Palmer, second president of the New Jersey Zinc Company. His name lives on in Princeton in Palmer Square, Palmer Hall, and Palmer Stadium.
Between Sterling Hill and Franklin, so much zinc ore had to be processed that a huge smelting and refining complex was built especially for this purpose in Pennsylvania. Why there? Because of the anthracite coal mines and the Lehigh Canal. The mines furnished the fuel necessary to smelt the ore, and the canal allowed bargeloads of coal to be transported to the smelter at low cost. Thus was born the town of Palmerton. [Think about that — a modern and still-thriving town in Pennsylvania was founded because of zinc mines in New Jersey!]
The historical significance of Sterling Hill is a matter of public record. Sterling Hill was placed on the New Jersey Register of Historic Places in July 1991 (ID #2621) and on the National Register of Historic Places in September 1991 (National Register Reference # 91001365).
Sterling Hill mine was the last operating underground mine in New Jersey. It closed in 1986 after more than 138 years of almost continuous production.
Want to know more? Several fine publications on the history and mineralogy of the Franklin-Sterling Hill area are available; for details and ordering information click here. Two of the most important publications, together with much additional information and photographs, are available on a web site built and maintained by Herb Yeates, a museum associate.
The Oldest and Most Spectacular Mica, Feldspar,
Beryl, and Uranium Mine in the USA.
Open Weekends from
May 15 through June 6, 2010
June 12 through October 17, 2010
Children (4-11) $13
Children under 4 are Free with a paid adult.
July & August 9am-6pm
Last ticket sold 1 hour before closing
The mountains and valleys of New Hampshire are rich with mineral formations. From the southwest corner of the state near Keene to the northern Canadian border near Littleton there are fascinating deposits of a variety of minerals. One of these deposits is known as the Littleton Formation which was formed during the Devonian era approximately 300,000,000 years ago. The mining of these mineral deposits has been an important part of New Hampshire history from prehistoric eras to the present. The Ruggles Mine, in Grafton N.H., is part of the Littleton Formation and has a rich mining and geological history. It is the oldest and largest mine of its kind in the United States. Minerals such as Mica, Feldspar, Beryl, and Uranium were mined at Ruggles for 175 years.
Minerals and rocks fall into three classes of identification, metamorphic, igneous, and sedimentary. All of these mineral formations are found in New Hampshire. Metamorphic rock is formed under extreme conditions of heat and pressure. Igneous rock is formed when magma or molten rock cools and solidifies. Sedimentary rock is formed when wind or water deposit sediments and the sediments become compacted. Sedimentary and igneous rock can become metamorphic under certain conditions of intense heat and pressure in the crust of the earth. Metamorphic rock can also change into another type of metamorphic rock. Heat and pressure do not change the chemical makeup of parent rocks but they do change the mineral and physical properties of those rocks.
The Littleton Formation is classified as a metamorphic rock formation that was originally sedimentary. New Hampshire was at one time completely covered by the sea. As a result, huge amounts of sediment were deposited. Hadley and Chapman describe what occurred during the prehistoric era in New Hampshire.
How Rocks were Made
In early Devonian time, sand and mud were deposited. Thousands of feet, in alternating layers, accumulated to form the Littleton formation. William Barton explains what happened during the metamorphism. For untold years the sediments slowly accumulated on the ocean bottom. The earlier layers, compressed by continually increasing weight of newer overlying sediments, were changed into the sedimentary rocks called sandstone, siltstone, and shale. Eventually these layers of rock grew to be several miles in thickness. The Great Folding and the Rise of Molten Rock; Sometime near the close of the Devonian period, about 300,000.000 years ago, a period of great crustal unrest set in. Western New Hampshire, which for a hundred million had been dominantly a region of wide spread seas, began to be uplifted, never again to be covered by marine waters. This period was marked by two major phenomena; intense compression of the earth’s crust and the rise of molten rock into the crust.
Great compress ional forces, acting horizontally in a more or less east-west direction, squeezed the rocks and forced them to buckle. Gigantic folds, both upwards and downwards, trending north and south were produced.
The accumulation of buried sedimentary rocks were heated, squeezed into great folds, and shattered. The heat and pressure involved were so great that the mineralogical character of the rocks changed entirely. The new rocks were called metamorphic and were characterized by mica schists. The schishts consisted of mica and quartz, with the shiny mica flakes having formed from the pre-existing dull clay particles Without these enormous upheavals and pressure New Hampshire would not be as mineral rich as it is today.
The Littleton formation is primarily mica schist, and surrounds the Ruggles pegmatite. Although there are many pegmatites throughout the Littleton formation, the Ruggles Mine is unique because of its enormous size. The crystal formations within the Ruggles pegmatite are larger than any other ever discovered here in New Hampshire. It is 1640 feet long and 335 feet wide, and is approximately 250 feet deep.
Pegmatites are very coarse-grained igneous rocks, that is, those in which the grains range in size from 5 millimeters to 3 centimeters. The course grain results from the presence of volatiles during the crystallization, thus permitting large crystals to grow; The Pegmatite is light colored because it consists almost entirely of light colored minerals: Plagioclase and perthite feldspars, quartz and muscovite mica.
Over one hundred and fifty minerals have been identified in the Ruggles Mine. The primary mineral of economic interest was mica. Books of mica as large as five feet in diameter have been discovered. Without human intervention, these mineral deposits would never have enriched N.H
The Discovery of Mica
Mica was first discovered in 1803 in Grafton N.H. by a man named Sam Ruggles. It is believed that his origins were English and that he was probably farming and homesteading when he discovered mica on his property. Sam Ruggles knew the value of the mica he had discovered and set forth the first and one of the largest mining operations of its kind in the United States.
For years it is believed that Sam Ruggles went to great lengths to keep the location of his mine a secret. Ruggles put his family to work extracting books of mica. Then, to prevent his neighbors from learning of his discovery, the mica was packed into wagons along with farm product sand transported by ox-team to Portsmouth, N.H. From there it was shipped to England, where it could be sold without arousing anyone’s suspicion as to its possible origin.
As the demand for mica increased, Ruggles would make special trips to Portsmouth in the dead of night, still hoping to keep the location of his mine a secret. There is speculation as to why Ruggles was so adamant about keeping his mine a secret. One possibility is that land was being claimed and not purchased in the early 1800s and there was an acre limit on how much land could be claimed each year. Ruggles may have been trying to claim enough land to cover the entire mountain top to ensure ownership of all the mica outcroppings. This illustrates the value of these resources to N.H.
In the early nineteenth century mica was in great demand for its use in many household products. Because mica is heat resistant and transparent, it was used for the windows in woodstoves and whale-oil lamps. Mica was also used in ships windows. Basically anything that is now made of glass was made of mica in the early 1800s.
By 1840 it was said that 600 to 700 pounds of mica were mined annually, valued at $1500. By 1869 production had increased tremendously, and in that year it was reported that seventy-five boxes weighing 350 pounds each had been mined, making a total of 26,000 pounds.
The production of mica continued to increase into the late 1800’s. The Ruggles Mine reported shipping 3,600 pounds in January of 1877. By the early to middle part of the twentieth century mica mining began to decline. In 1930 as little as 8,000 pounds of mica was mined annually in the United States.
Despite the decrease in production, the value of mica remained high. Clear sheets of mica were still sold at very high prices, and by the early 1930’s an estimated $12,000,000 worth of mica had been mined at the Ruggles Mine.
Later on mica was used as an electrical insulator. It does not conduct heat or electricity due to its molecular structure. Early electrical appliances, such as toasters had mica in them. Mica is still being used today in products from building materials to cosmetics. Mica is in cement blocks and asphalt roof shingles. It is also used in lipsticks and fingernail polish. Most anything that sparkles contains mica.
The Development of Ruggles Mine
The ownership of the Ruggles Mine has changed several times over the years. It is not certain who owned the mine after the death of Sam Ruggles and for much of the rest of the nineteenth century. In 1874, a man named J.W. Kelton is said to have owned and operated the mine. By this time the mica was no longer being hauled away in secret by ox-cart, but being transported out of Grafton by the railroad.
Feldspar was the second most predominant mineral to be of economic interest at Ruggles Mine. The American Minerals company began mining feldspar in 1912. Feldspar was used in the making of high grade ceramics. The Syracuse China company used feldspar in the glazes on their fine china for many years. It was also used in the enamel surfaces of early appliances such as stoves and refrigerators. Feldspar was also in the making of false teeth.
The Bon Ami Company owned and operated the Ruggles Mine between 1932 and 1959. They mined the feldspar for use their non-abrasive scouring powder and glass cleaner. The Bon Ami Company extracted approximately ten thousand tons of feldspar a year during their period of operation.
Beryl is another mineral that was mined at Ruggles Mine. Beryl is the principal ore of the metal known as beryllium. Beryllium is lighter than aluminum and stronger than steel. Today, beryllium alloys are used in atomic reactors, electrical components, and as metal on spaceships components used at NASA. At one time during the mining of Beryl, a mass of the mineral was discovered that filled three freight train cars.
During the twentieth century The Ruggles Mine was reworked several times for the scrap mica that was left behind during earlier operations. The large “books” of mica were no longer being mined, but the smaller amounts that were dumped into waste piles during earlier operations. As new uses for mica were discovered, the demand for it increased once again. It was no longer used for whale-oil lamps, as in days of Sam Ruggles, but now in wallpaper (for sheen effect), paints, roofing, molded insulation, lubricants, etc. All the better grades were used for electrical insulation. The reworking of the mine was done by the English Mica Company of New York. They set up an extensive operation that crushed, screened, and washed the rock to separate it from the mica. The recovered mica was then washed down 3,200-foot flume to a mill at the bottom of the hill.
The Mine remained active and productive for 160 years. In the early 1960’s the U.S. government discontinued subsidizing the mica industry though it’s Mica Stock Piling Program. The result was that domestic mica mining operations could no longer compete in price with the mica imported from Brazil and India. Mining operations were thus discontinued at the Ruggles Mine.
The end of mining mica and other minerals ended an important chapter in the history New Hampshire. Mining provided employment and revenue to many people during the early days of our state. It provided our ancestors with an option to farming as means of survival. The Littleton Formation and the Ruggles pegmatite are what is left of a very significant part of geologic history. The formation was a natural resource that provided income and numerous minerals used in many important products.
In 1963 the Ruggles Mine was opened to the public. For 40 years visitors have been able to come and experience a part of this geologic and mining history. When entering the mine today one can still see where the feldspar and mica of the pegmatite connects to schist of the Littleton formation. One can witness the tremendous forces of the earths folding by observing the layers of schist that stand vertically above the pegmatite. The collecting of minerals is permitted at the Ruggles Mine, one can take home pieces of this history. Exploring the enormous caverns and tunnels provides insight into an event that took place 350,000,000 years ago. A visit to Ruggles provides insight into an important part of mining and geologic history.
Feed your gold-bearing gravel into the upper portion of the sluice box in carefully regulated amounts. Do not, under any circumstances, dump a large amount of gravel into the sluice box all at once! The gravel must be fed at a pace that will not overload the riffles. How can you tell when the riffles are overloading? It is simple. If you cannot see the uppermost “crest” of each riffle bar at all times, you are feeding the gravel too fast. Back off a bit. The use of a 1/4 inch classifier screen to pre-screen material before dumping into the sluice box can save much time and effort. The penalty for overloading your riffles often resullts in lost gold! Each time a new load of gravel is dumped into a sluice box with overloaded riffles, any gold in that gravel will wash right over the material that is clogging your riffles and out the discharge end of the box.
Welcome to the Rainbow Ridge Opal Mine
Virgin Valley, Nevada
Rainbow Ridge Opal Mine is located in Northwest Nevada, approximately 135 miles from Winnemucca, Nevada, and approximately 100 miles from Lakeview, OR. The closest town is Denio, NV, which is 35 miles away. Denio Junction has reopened and food, fuel and rooms are available. We recommend that you fill up in either Lakeview or Winnemucca on your way out to the mine. All roads to the mine are blacktop, except for the last 7.5 miles, which are gravel and dirt. During wet weather, the last couple of miles is very bad, and should not be attempted, (looking for opal in wet or very overcast weather is not good anyway).
There is no overnight camping available at Rainbow Ridge. Trailers should be left at the CCC camp, which is 5 miles before you get to the mine. Denio Junction has reopened and food, fuel and rooms are available. We recommend that you fill up in either Lakeview or Winnemucca on your way out to the mine.
The opals from Rainbow Ridge are casts after wood, and are some of the most beautiful opals in the world. We offer tailings digging where many different wood and opal combinations may be found. The tailings are up to eight feet deep. We turn the tailings from time to time, and are constantly adding to the tailings from the virgin ground loads. The virgin ground loads are materials taken from the bank with the loader, and are worked on a flattened area near where you park. Everything you find, regardless of value, is yours to keep. Although luck plays a part in finding opals, an “educated” eye is very helpful. First timers will be given some help in getting them started.
Rainbow Ridge Opal Mine
2010 Season Information: Opening Date: Friday, May 28th through
Last Digging Day: Sunday, September 19th.
Please note thet we are closed on Wednesdays and Thursdays during the 2010 season.
Reservations for the virgin ground loads will be accepted by phone only, NO EMAIL RESERVATIONS, begining April 15th thru the last day of the season.
Please call: (775) 941-0270 or (541) 548-4810 to make a reservation.
Virgin Ground Load Fee this season is $500.00, and will admit either one or two adults.
Tailing Fee is $70.00 per person per day, and children10-15 are still half price.
SUGGESTED ITEMS TO BRING WITH YOU:
Small pick (sharp, single hand)
Small garden rake
Small shovel or trowel
Spray bottle with water for cleaning off dirt
Buckets (5 gallon) for collecting specimens, plus an extra one for a seat
Sun block, hat, and gloves
Come visit our rock shop; we have lots of beautiful opal for sale, as well as fossils, minerals, and jewelry. We have digging tools and buckets for sale, too.
Want your own piece of amber but don’t have the money to buy a sample? Here’s a way to make your own fake amber
You Will Need
A dead insect (look on window ledges or on spider webs)
Plastic pop bottle cap
clear nail polish
tweezers or needle-nose pliers
What To Do
1. Place the pop bottle cap, empty side up on the newspaper.
2. Use the tweezers to drop the dead insect into the empty cap
3. Place several drops of yellow food colouring into the clear nail polish. Close the polish and shake to mix the colour. If you wish you can also add a drop of red food colouring to the polish to make a more amber colour
4. Drip the polish over the dead bug and put in a safe, out of the way place to dry.
This was submitted by a reader. I have not tried this myself but please email me results if you try.
Quick Tip: Telling real Amber from Plastic forgeries…. One of the simplest non-destructive tests that you can do yourself is to clean and taste the specimen. Carefully washing with soap and water, then with just water, should leave a clean specimen ready for this test. Lick the specimen slowly several times, allowing the subtle taste to linger. It should be extremely subtle – real amber has almost no taste at all, leaving at most a very slight, tingly sensation. We think this “taste” may actually be just a touch sensation, not a true response of the taste buds. Most plastic or other polymer forgeries, on the other hand, carry a distinctly nasty taste that screams, “Imitation!” Don’t be fooled, remembering this simple taste test can save you considerable trouble in your adventures with amber.
A pegmatite is a very coarse-grained, intrusive igneous rock composed of interlocking grains usually larger than 2.5 cm in size;such rocks are referred to as pegmatitic.
Most pegmatites are composed of quartz, feldspar and mica; in essence a granite. Rarer intermediate composition and mafic pegmatites containing amphibole, Ca-plagioclase feldspar, pyroxene and other minerals are known, found in recrystallised zones and apophyses associated with large layered intrusions.
Crystal size is the most striking feature of pegmatites, with crystals usually over 5 cm in size. Individual crystals over 10 meters across have been found, and the world’s largest crystal was found within a pegmatite.
Similarly, crystal texture and form within pegmatitic rock may be taken to extreme size and perfection. Feldspar within a pegmatite may display exaggerated and perfect twinning, exsolution lamellae, and when affected by hydrous crystallization, macroscale graphic texture is known, with feldspar and quartz intergrown. Perthite feldspar within a pegmatite often shows gigantic perthitic texture visible to the naked eye.
Crystal growth rates in pegmatite must be incredibly fast to allow gigantic crystals to grow within the confines and pressures of the Earth’s crust. For this reason, the consensus on pegmatitic growth mechanisms involves a combination of the following processes;
Low rates of nucleation of crystals coupled with high diffusivity to force growth of a few large crystals instead of many smaller crystals
High vapor and water pressure, to assist in the enhancement of conditions of diffusivity
High concentrations of fluxing elements such as boron and lithium which lower the temperature of solidification within the magma or vapor
Low thermal gradients coupled with a high wall rock temperature, explaining the preponderance for pegmatite to occur only within greenschist metamorphic terranes
Despite this consensus on likely chemical, thermal and compositional conditions required to promote pegmatite growth there are three main theories behind pegmatite formation;
Metamorphic; pegmatite fluids are created by devolatilisation (dewatering) of metamorphic rocks, particularly felsic gneiss, to liberate the right constituents and water, at the right temperature
Magmatic; pegmatites tend to occur in the aureoles of granites in most cases, and are usually granitic in character, often closely matching the compositions of nearby granites. Pegmatites thus represent exsolved granitic material which crystallises in the country rocks
Metasomatic; pegmatite, in a few cases, could be explained by the action of hot alteration fluids upon a rock mass, with bulk chemical and textural change.
Metasomatism is currently not well favored as a mechanism for pegmatite formation and it is likely that metamorphism and magmatism are both contributors toward the conditions necessary for pegmatite genesis.
The mineralogy of a pegmatite is in all cases dominated by some form of feldspar, often with mica and usually with quartz, being altogether “granitic” in character. Beyond that, pegmatite may include most minerals associated with granite and granite-associated hydrothermal systems, granite-associated mineralisation styles, for example greisens, and somewhat with skarn associated mineralisation.