Herkimer Diamonds Science and Formation

Are all Herkimer Diamonds double-terminated quartz crystals? The answer is yes. Does that make all double-terminated quartz crystals Herkimer diamonds then? The answer is no.
Herkimer refers to the location of these unusual quartz clusters found in hollow “pockets.” Herkimer County is about a 4 and a half hours drive north of New York City. The name Herkimer comes from an American Revolution General named Nicholas Herkimer who died in battle in 1777.

Now the source and formation of Herkimer Diamonds is of particular interest to us here at American Geode because the Herkimer Diamond was formed in “pockets” not unlike the pockets that formed geodes. Most quartz crystals grow, over the course of millions of years attached to a matrix, attached to the surrounding rock or stone. So in those formations only one end of the quartz crystal grows to its point. With Herkimer Diamonds forming inside pockets, freed from the surrounding matrix stone, they grow points on both ends.

The Herkimer Diamond began forming nearly 500 million years ago in pockets within a sedimentary rock called Dolostone (Dolomite + Limestone). Sedimentary rock, different from its two cousins Igneous rock and Metamorphic rock, is formed by layers of mineral and organic matter under hundreds of million years of pressure. As more layers of mineral and organic matter are deposited, this increases the pressure and weight on the lower and earlier layers of sedimentary rock below. The Dolostone covered Herkimer County during the Cambrian Age, when Herkimer County was also the bottom of the sea that spanned across North America.

Now this is the part of the Herkimer Diamond formation that is similar to the way geodes are formed: organic material, plants and sea life would die and be buried under new layers of sedimentary stone. When these plants and other sea life would decompose under the rock, they release gases, and this gas is what formed the “pocket.” Evidence of this organic, plant material succumbing to decomposition is clear when you see the black shiny flakes of Anthraxolite that surround or leak from these pockets. Anthraxolite is a carbon compound and by-product formed when organic material breaks down.

So as the organic material decayed and broke down it became a gas, trapped below layers of sedimentary stone. Air creates its own pressure inside a substance, so the air pressure was carving out its own cavity from the inside out. These air pockets became the pockets we rockhounds discover as we crumble, break, and peel away layers of the dolostone. Over the course of 200-250 million years the layers of sedimentary rock increased and grew, and this increased the pressure and heat on the buried dolostone. Also inside each of these air pockets were various quartz and carbon elements and other compounds “feeling the heat” from being buried below layers of sedimentary rock.

Under this pressure of the sedimentary layers of rock, and the ensuing heat, the quartz and other compounds inside these pockets began to transform themselves. Finally, over the course of 300 million years, the glaciers that sat atop Herkimer County began to melt, and washed away layers of the sedimentary rock, and allowed the compounds and elements inside these pockets to cool down, and crystallize.

An important question to answer right now is “why are the Herkimer Diamonds double-terminated?” The answer is that quartz does not adhere to dolostone, so the quartz trapped inside these air pockets trapped in dolostone did not adhere to the surrounding matrix stone. This left the quartz crystals free to crystallize unattached to matrix stone, and allowed both of their ends to grow into terminated points.

Many Herkimer Diamonds are found attached to one another in a cluster. They did adhere to one another during their formation, but again did not adhere to the dolostone interior of the air pocket.

The value of Herkimer Diamonds is determined by their size, and by how opaque, or translucent they are. The more translucent and bigger Herkimer Diamonds are worth more to a collector or jeweler than the smaller opaque specimens. Knowing the history and background of the Herkimer Diamonds however lends a premium in our opinion when you are considering adding Herkimer Diamonds to your collection. They are not commercially mined due to various New York state laws limiting mining in the state, and most of Herkimer County is being used today by grazing cows, apple orchards, tart cherry trees, farms of squash, cabbage and onions, and wine grapes.

We have recently gained access to heretofore unmined and barren acres in the Herkimer County area on the same geologic slope and ledge as the traditional Herkimer Diamond mines.
We are in consultation right now with the owner about constructing a pole-barn over this new Herkimer mine so we can mine year-round. to keep updated on this exciting new venture to discover the first new Herkimer Diamond mine of the 21st century.

November 2015 New York Gem and Mineral Show Discount Ticket

November 2015 New York Gem Mineral Show Discount Ticket

Print out this discount coupon, or show it from your phone at the entry booth!

Our friends at the New York Mineralogical Club and Excalibur Mineral Corp. are hosting the November gem and mineral show here in New York City.

This is a gem and mineral show we attend every year. As you enter the show, your first exchange will be with the New York Mineralogical Club, our beloved home base, and you will have a chance to join the club, or just learn about the club. Join the club however for some great prizes and gifts.

Now the show itself is full of the top dealers in and around New York City. You will have the chance to acquire very fine high-end pieces, very large display mineral and geode specimens, museum grade fossils, interesting one-of-a-kind artwork, as well as fine gemstone jewelry.

Make the trip the beginning or part of your day in New York City. You are not far from the American Museum of Natural History, and very close to the American Folk Art Museum, which is free admission.

We hope to see you there. Contact us via our “Contact Us” button if you would like to meet at the show, or at the hotel bar or after the show!

Print out this discount coupon, or show it from your phone at the entry booth!

November 2015 New York Gem Mineral Show Discount Ticket

Promote your Gem and Mineral Club

For the most up to date gem and mineral events and shows, check out our Gem, Mineral, and Fossil Newswire.

Does your gem, mineral or fossil club or society need new members in your ranks? How about new guests to your gem, mineral and fossil shows? Would you like rockhounds and gem, mineral and fossil enthusiasts to travel across state lines to visit your show? Would you like exponentially more traffic to your club’s homepage or the show’s homepage?

American Geode can help. Between 3000 and 10000 rockhounds and gem, mineral and fossil enthusiasts visit our website each month. They also contact us for suggestions on clubs to join, and shows and events to attend.

Other mineral websites charge between $600 to $1000 per year for a banner ad on their site.

We charge a flat rate of $150 for 12 month basic partnership and offer much more than other mineral sites. Send us two banner ads, 728×90 and/or 150×150, that we will post on our website. As an add-on service, send your club announcements and show announcements for us to post over our famous Twitter feed American Geode Twitter with our nearly 3000 rockhound followers, fans and friends.

The benefits to you and your club are that you will raise higher in the Google ranks when someone searches for gem and mineral clubs, and gem and mineral shows. You will also view many more visitors to your site, soliciting information about how to join your club, download your member application form, and visit your shows.

We make it very easy for you. We can use your club’s logo for the ad, or we will craft a banner ad that uses your club’s logo. Take a look at the example of a club banner here: Wildacres info page.

So please click the “Contact Us” button our homepage and let us start promoting your gem and mineral club, and fill up your gem and mineral shows with new and young rockhounds.

For the most up to date gem and mineral events and shows, check out our Gem, Mineral, and Fossil Newswire.

Smoky Quartz Mining in Devil’s Head, Colorado

Colorado is famous for gems, smoky quartz in this locale, minerals, rockhounding, prospecting and mining. Joe and I certainly experienced that in the spring when a friend and mineral dealer hosted us for a weekend of mining, prospecting and rockhounding.
We drove for many hours through through the Pike National Forest, where one finds Pike’s Peak, until we came to an area, a mountain side known as “Devil’s Head.” Now this style of rockhounding means you take a pick-axe, start mining to clear overgrowth and topsoil, and once you hit the surface rock, you are surprisingly close to the layer where one finds smoky quartz.
Joe was very lucky and discovered a vein of smoky quartz with the first spot he chose. I was not so lucky, but we did see the the beauty and majesty of Pike’s Peak and the entire Pike National Forest.

If you have the jeep to make this long drive, over dirt roads, we recommend this rockhounding trip. Take plenty of water, more than you would normally as the height where you are does dehydrate you much more quickly than when you rockhound elsewhere. The air is so dry, and you are at such a height you don’t sweat, so you can’t tell how dehydrated you are becoming.

Colorado is a beautiful natural treasure in America. If you get the chance just to drive through the Pike National Forest, opt for it.
For the most up to date gem and mineral events and shows, check out our Gem, Mineral, and Fossil Newswire.


Pegmatite and Amazonite Mining in Lake George, CO

Joe, our friend Leonard and I drove for nearly three hours, through the National Forest containing Pike’s Peak, up 15 degree inclines that felt like 22 degree inclines to get to this private claim to crack pegmatite in search of amazonite. The whole notion of private claims fascinates me, and is something I will write about in the future. This gentleman who was hosting us there had staked a claim to this public land in the National Park, for the purpose of mining. Now there are fees, and papers to file, and annual steps to follow, but to have a mining area to yourself is something that ended up appealing very much to Joe and myself.
The game plan was simple – find a spot, and start clearing the topsoil and coverage, hit rock, and start mining.
This kind of mining in Colorado requires a lot more luck than Herkimer Diamond for instance. There is simply such a vast area in these Colorado claims that you really have to decide to devote your time to one hole, digging deeper and deeper, or do you hit more areas, seeking more pockets, and spread out.
We had a crew of 5, 6 if you include the canine friend seen in the photos, and while none of us hit a grand jackpot pocket, we did uncover some very nice amazonite that we were able to sell very quickly a month later to some collectors at the Herkimer Gem Show.
I don’t know how to recommend this mining expedition, or how to grade it or offer hints. It was a private claim, and I will likely never return. But this adventure was an inspiration for me to learn more about staking a claim. If you are near New York, and would like to discuss the whole process of staking a claim, please “Contact Us” through our site.
For the most up to date gem and mineral events and shows, check out our Gem, Mineral, and Fossil Newswire.