Collecting Pyrite Crystals at Navajun, Spain

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by Eric S. Greene

Having the chance to collect pyrite at Navajún, Spain has been #1 on my bucket list since I first saw specimens from Mina Ampliación a Victoria. Now, after a buying trip to Sainte-Marie-aux-Mines in France, my dream was about to come true. It was the 4th of July. My wife Jeanne and I were celebrating America's Independence Day by visiting the Guggenheim Museum in Bilbao, then heading south to Navajún to meet mine owner Pedro Ansorena Conde and dig for pyrite. The drive from Bilbao takes about 3½ hours on a superhighway that passes over and around rolling hills and mountains studded with state-of-the-art windmills and field after field of wine grapes, wheat and hops. The last 40 km of the trip takes over an hour because the road winds through small villages and up, down and around hairpin turns on the way to our destination.


Wheat fields outside Navajún

We met Pedro at his inn, Casa Don Pedro in Navajún, and he ushered us into the reception area. Our spacious and comfortable room was on the second floor, with a large bathroom just down the hall. In the morning, after Pedro fixed us breakfast, we hopped into his SUV and headed for the mine. The drive is only 2.4 km on a well-maintained dirt road that begins just outside of Navajún. The road climbs the side of a rolling ridge, passes through a gap at the top, and then descends into the cleft between two hills to the site of the mine.


Pedro's inn in Navajún

Driving into the mine, the first thing I saw was the 60 meter high rock wall towering over a pit that has been excavated over the last 43 years. To the west were piles of debris, which had been dumped in carefully arranged rows and terraces. The quarry wall is layered with over a dozen strata of varying colors, including a pale red ochre, whitish tan, light gray, or medium gray. The levels vary in thickness from a meter to about 5 meters, and the colors repeat as they climb up the wall.

Mina Victoria is one of the few Spanish mines that is quarried exclusively for mineral specimens. Here, pyrite crystals are exposed in three different layers in a cut that is 40 to 50 meters deep. Layer one is the lowest level, and layer 3 the highest. The thickness of these layers ranges from 1 meter to 3 meters, with an average of about 2.5 meters. The strata strike east-west, with a dip of 15º south. Within each strata there are differences in both crystal morphology and the degree of oxidation of the pyrite. Strata one has been the focus of most mining to date, as it has produced the most spectacular specimens. Strata two was at one time worked using horizontal open galleries with concrete pillars for support, but is not currently in production because of safety concerns. Specimens from this layer are generally of lower quality than those in the first layer, though some good matrix specimens were found. Strata three remains in reserve.


The town square in Navajun.

When we arrived at the mine the sun was behind the quarry wall, providing shade for two men in blue coveralls who were in a cleared area near the bottom. This exposed area, 25 meters long and 15 meters wide, had been dug down between two side walls that were about 4 meters higher. The area to the east was fairly flat, and ran to within 5 meters of the towering cliff. The exposed area was an astonishing sight, as everywhere I looked I saw hundreds, thousands - no, hundreds of thousands of sharp, metallic brassy gold pyrite cubes sparkling in the sun. Where the cliff had been cut to the right depth, cubes of all sizes dotted the whitish tan matrix everywhere I looked. The cubic pyrite crystals here are so perfect, so smooth, and so shiny that it seems impossible that Mother Nature could have possibly made them herself, with no humans doing cutting or polishing. For a die-hard field collector like me, the effect was overwhelming. Never had I seen so many superb crystals exposed in such overwhelming abundance. The extravagant profusion of thousands of beautiful pyrite crystals spread out before me was almost overwhelming. I was stunned and speechless.


View of the south wall of the mine.

Pedro fitted us out with hard hats, and then took us on a tour of the mine. He pointed out various geological features, especially the three crystal-bearing strata that are exposed in the cut. He talked about using the heavy equipment at the site, including a big excavator to remove overburden, and a loader and dump truck to haul away waste rock. I was especially interested because of my experience mining with heavy equipment at Treasure Mountain Diamond Mine in New York and at the William Wise Mine in New Hampshire. I was amazed again when he said the crystal stratum he had just finished uncovering averaged about 2.5 meters thick, but was up to 5 meters in places. If you do the math, the volume of just this one recently-exposed cut contained over 225 cubic meters of pyrite-filled matrix!


Pyrite cubes to 8 cm in the quarry wall.

There had already been some terrific specimens uncovered, of course. For example, Pedro pointed out an area on the wall where a cluster of half a dozen pyrite cubes to 15 cm were sticking out of the matrix. He said he would remove that later with power tools to make sure it was not damaged. He also mentioned that in one of the recently uncovered crystal layers he had found a 17 cm long rectangular pyrite crystal, the largest so far this year.


View of the active digging area in early July 2013.

Next he showed us several areas where we could dig, but then changed his mind and brought us over to where his two miners were working. They had each cut a half-meter high bench into the crystal bearing layer, and were extracting matrix specimens, loose crystals, and groups from the near-white marl layer. The crystals were sharp and brilliant cubes, up to 4 cm on edge, and they stood out in high relief from the matrix. This was definitely an artisanal operation, as the men were using nothing more than small hammers, thin pointed chisels, and a small pry bar to pry out the plates. Pedro pointed to a spot just to the right of the two men, and said, "You can dig here." We were excited!


A mine worker trims a matrix specimen

We hiked up to the storage trailer and picked up hammers, chisels, a small hoe, a big blue plastic box to carry away our finds, and lots of newspaper to wrap up the crystals. Before we began, we watched the experienced miners to learn the refined techniques they had developed over the years. First, they delicately hammered and chiseled their way under and around chunks of matrix in the bearing layer, then pried out plates up to half a meter long, each dotted with 2 to 5 cm crystals. They picked up the loose crystals that had popped off the plates and wrapped them in newspaper. Then they picked up the rest of the loose crystals and put them aside on newspapers for later wrapping. It looked so easy! I was dying to try it myself, so I returned to my spot (less than three meters away) to begin digging.


View of some of the heavy equipment and the north and east walls of the mine.

To start, I picked out an area about two meters wide and cleared off the debris left by the excavator, exposing the un-worked marl layer underneath. What should have taken a few minutes ended up taking almost an hour, as there were so many cubes that I couldn't bear to just throw them aside. So, I examined each one and picked out the most perfect, unbroken crystals with no chips on the edges or corners, and placed them in neat rows on a couple of sheets of newspaper. As I used the hoe to drag away the loose material, I found several nice pieces, including some intergrown groups of crystals and a few choice matrix specimens. These I wrapped individually and placed in our blue box. Finally the matrix layer was exposed, and of course everywhere I looked there were more cubes sticking out. Where to start? I decided to do as the workers were doing, and try to extract some matrix plates. This was not as easy as it looked, because the matrix was relatively soft, and tended to come apart rather than staying in one piece. And, if I hammered too vigorously, the crystals just fell out of the matrix. The area where I started working was wet, and the marl was the consistency of stiff putty. Although this made chiseling extremely easy, it also meant I could not collect any matrix pieces. Then, to my surprise, out of the putty came a 3cm cluster of interpenetrating crystals! As I continued working, more of these unusual pieces emerged, and I soon covered the top of a folded piece of newspaper with them. Once it was full, I stopped and wrapped each gem-like group individually and added them to our box. After working this area for a few hours, I gave Jeanne this easy-to-work spot, and moved a couple of meters to the right to look for an area with harder matrix.


Mine worker with a box of loose cubes and another box with matrix specimens wrapped in newspaper.

By this time it was 12:30, and when the sun suddenly emerged from behind the towering quarry wall, it pushed the temperature up over 34ºC (93ºF). Though it was not humid, the heat was very uncomfortable, so I went up to Pedro's equipment area and borrowed a beach umbrella. This provided some welcome shade, so we stopped to eat lunch, and then went back to work.

I noticed that Pedro's workers were collecting loose pyrite cubes and laying out similar-sized cubes in a single layer right up close to each other on newspaper, then folding up the paper to make thin, compact packets. Because each cube was held tightly in place by its neighbors, this ensured they would not be damaged. Copying these professionals, I began to assemble packets like this, going through the piles of cubes looking for the most perfect, undamaged examples, lining them up in tight rows, and folding them into packets.


Jeanne Greene digs into the wall in our collecting area

At 3 PM, the heat became overwhelming, and the workers packed up and prepared to go home. We followed suit, and Pedro drove us back to the B&B, where we settled in for a nice siesta. The old stone house was comfortably cool, and we read and dozed for a while in the afternoon. About 5 PM we drove back to Aguilar to buy picnic supplies for the next few days. At 7:00, Pedro arrived and began fixing our dinner. And what a treat it was: regional blanched asparagus with grated truffles, green salad with fresh-caught shrimp, roasted local lamb, and fresh-dug potatoes, followed by a delicious home-made dessert. The man not only knows how to take pyrite from the ground, he knows how to cook! We sat and talked with Pedro after dinner, posing questions about the history, geology, and mineralogy of the mine, as well as about how Pedro had created such an unusual life for himself. By 10 PM we were in bed, dreaming of finding giant pyrite cubes the next day.


Matrix specimen shortly after removal with pyrite cubes to 5 cm.

The following two days went by as in a trance, as Jeanne and I spent both days collecting pyrite from 9 AM to 3 PM, then returning to the B&B for R&R, then another gourmet dinner (think fresh tuna, lamb cutlets, and crunchy fresh vegetables) with everything local and expertly prepared. On Sunday afternoon, our last day, Pedro took us to his facility in Aguilar where he preps, cleans and boxes all the specimens from the mine. The L-shaped building was formerly used to store grain, but Pedro has completely transformed it for his enterprise. One end of the "L" is devoted to storing material direct from the mine, awaiting preparation. When we were there, it was only about one-third full, though often it is at maximum capacity. The other end of the "L" houses a series of areas where specimens are made ready for sale. Pedro employs two workers who do all the preparation. The entire operation is highly organized, with several rooms that are specially designed for each task. There is a room where specimens are trimmed, and the marl matrix removed around each crystal to expose it to its maximum potential. This is done using pneumatic pens and micro-grinders, tools commonly used to prepare fossils. Many of the specimens emerging from this step are ready for sale, so they are sorted and boxed and moved to the final room on the ground floor that holds flats of specimens ready for sale. Water is never used to clean specimens, because clusters can disintegrate and crystals pop off matrix if the bone dry marl absorbs water and swells.


Jeanne Greene inspecting cleaned specimens in the warehouse.

In the next room, the workers deal with specimens requiring reconstruction. The original groups of crystals are carefully wrapped back at the mine, and kept together until processing. The restoration varies from simply gluing cubes back into the holes where they fell out of the matrix, to reconstructing complex clusters of interlocking crystals, on rare occasions including as many as a hundred crystals when complete. The crystals are meticulously fitted, then glued into their precise original positions using a specially formulated cyanoacrylate resin. Upstairs in this building Pedro has an office and a display of some of his finer pieces for sale.


Mine owner Pedro Ansore Conde in his warehouse.

IF YOU GO

The prospect is owned by Piritas de Navajún S.L., and is only open to collectors by prior arrangement. The property marked "No Trespassing" and is patrolled.

  • Book in advance. The mine is not always open, especially when Pedro is away at a show. Also, consider going in the fall rather than in the summer heat or the spring rainy season. Authorized visits can be arranged through the website, www.piritasdenavajún.com.
  • Decide if you want to bring your own tools. A 4- or 6-pound hammer, medium and small chisels, and a pry bar (fewer crystals fall out when prying than hammering) would be most helpful. Or, borrow tools from Pedro. He also has hard hats, which are required in the mine.
  • Work slowly, and be as gentle as you can. When feasible, pry rather than hammer. Try to get pieces with crystals still in the matrix.
  • If it's hot, go early in the day, so you can work in the shade. When we were there, the miners arrived at 7 and left at 3.
  • Bring plenty of dry newspaper for wrapping material.
  • To get good clusters, carefully dissect the matrix then, if crystals come off of a cluster, note their exact locations and reassemble them later with glue.
  • Dress for comfort. Use sun screen.
  • Bring food and plenty of water.
  • Keep your eyes open. Look on the ground and turn over matrix pieces in roadways - we found many fine crystals lying loose on the ground, plus some great matrix specimens that were lying upside down.
  • There's no limit, so you can keep whatever you find. But beware of the impulse to take too much, especially if you are flying; pyrite is heavy.
  • Watch the workers to learn the refined techniques they have developed.

ABOUT THE AUTHOR

Eric S. Greene is president of TreasureMountainMining.com, an Internet mineral dealership specializing in fine mineral specimens. He is also an avid field collector and member of the Keene, NH Mineral Club.

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