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2020, Fluorite, Rucksack Cleft, Weisseck



During the many years of working in the “Ice Cleft” on the Weisseck, I often left my rucksack at a particular place nearby. This location always struck me as being suspicious; something of interest must be lurking beneath its surface, which being Weisseck, would be fluorite. Some minute signs even suggested that perhaps a very long time ago, people had been excavating fluorite.  For a number of years I played with the thought of taking a closer look.  As the location cannot be worked alone, I needed colleagues. And in Anton Baier and Michael Loidl, I found two splendid partners whose idealism and commitment proved crucial for opening that which would eventually be dubbed “Rucksack Cleft.” After a series of planning discussions during the winter of 2020, we were able start work in July 2020. On our first tour, we started to work right next to a small rock face. First we removed some larger boulders and then began excavating.

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Toni starts digging

After about an hour and a half of work and at a depth of about three quarters of a meter, we came across light-brown dolomite sand. The sand was streaked with thin veins of calcite and fluorite. A very good sign! A short time later, a small clay-filled cavity released the first small, shiny, good-quality fluorites. Now everything happened very quickly: while we were still laughing because we were digging up an old beer can from the seventies about 30 cm above the small cavity, my chisel fell into another cavity. I enlarged the spot to be able to see inside with the headlamp. As I lit the area with my headlamp, I knew we hit the jackpot! I had found a larger cleft. At the time, however, we had no idea how large this new cleft would become.

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 Light brown dolomite sand comes to light under the rubble

The beginning of the Rucksack Cleft: only a small hole for the time being, and it is not yet apparent that there is a large cleft behind it

The first fluorite

Toni watches me widening the cleft

The first look at the freshly opened cleft

 Look into the cleft through the enlarged hole: many loose specimens were waiting to be removed

Access to the cleft needed to enlarged once again. This was effortless as the surrounding rock was very soft. The first beautiful fluorite specimens were right at the beginning of the cleft. The pieces were just waiting to be picked up from loose rubble. What a feeling and what a great gift to be able to experience something like this! Less than three hours had passed since the work began, and now we were in high spirits. The many fluorites, sometimes closely stacked, fired our imagination. What treasures might still be waiting for us? Now the fluorite feast began. Each of us came to a "laid table"  and could enjoy several rounds of salvaging beautiful pieces.

One of the first freshly recovered fluorite specimens

We worked carefully so as not to damage the finds. Every now and then a lot more rubble had to be removed. The next few hours passed without any sense of time. During this phase, we always felt lucky when we unearthed a particularly beautiful piece. And the cavity kept getting bigger! Finally we had salvaged enough fluorite for the day. The finds were packed well and then we descended into the valley, heavily laden and overjoyed.

We had time to think until the next day and came to the following conclusion: If our suspicion was confirmed that this cleft is indeed very large, then we could not possibly finish working it this year. Michael and Toni had only limited vacations and I didn't want to spend the entire collecting season at this site alone. We decided to continue working the cleft briefly and intensively, and then to close it until next year. In addition, we decided something rather unusual among collectors: We agreed to take turns inviting different collector friends to help us and to share in the finds.

My son Lukas accompanied us the next day. I had told him about our new find, and he was dying to see the new Cleft. So there were four of us. Again we started very early. This time, too, we reached the site before 7 a.m. We started our work immediately. More fluorites were recovered and debris removed. In the beginning, Lukas had the right of way to work on the cleft. Soon we had to crawl upper body into the cleft to clear more debris. In the cavity, a square bucket would be filled with the debris - often with a beautiful fluorite placed on top - and then crawled backwards and pulled out of the cleft. An unpleasant and tiring job.

A nice piece from the cleft

We had to continue this way of working until there was finally enough space in the cavity for me to crawl into. Now the bucket was filled with rubble from the inside and passed from the inside out. Although it was very narrow in the cleft at the beginning, the work progressed faster now. With increased freedom of movement, I could now reach larger boulders and remove larger fluorite specimens out from the cavity.

A larger fluorite specimen from the cavity

The quality of the fluorites is getting better

As this activity proved to be very exhausting, we took turns. As the work progressed, Toni started sorting the fluorites. He packed the beautiful pieces well and put them in cloth sacks. Soon time ran out. The cavity was now about two meters deep, a meter wide and a meter high; clearly it was going to get much bigger. We would be able to extend invitations to additional collectors.

Lukas and I (standing), Michael and Toni (sitting) with larger fluorite specimens

On the next three tours, collector friends helped us open the cleft. Large boulders were broken up by chiseling, and brought out. Soon the ceiling began to worry us, as it no longer looked stable. For this reason we carried wooden beams and boards to the site and tried to stabilize the ceiling. After the belay work, I refocused on the bottom of the cleft and continued digging deeper. Bucket after bucket was lifted out of the cavity. Fluorite showed up only a little - the pace of work was very high. Whenever I had lowered one half of the cleft floor by about 30 cm, I changed position and continued digging on the other side. I had noticed that on the left side of the cavity (cavity looking inward), a fluorite-bearing layer was sloping down at about 45 degrees. The cavity obviously widened in depth. I traced this layer of fluorite and found a new nearly horizontal void half a meter below. With my almost one meter long cleft hook I could not feel any resistance there. I kept this discovery to myself as a surprise for my friends above ground. I removed some more loose rock material to give better access to the new cavity.

Working in the ever-expanding cavity

After half an hour enough rubble was removed. I knelt, leaned forward, and peered into the new cavity with my headlamp. What I saw there left me speechless at first and made my heart soar. Even after many years of working the Weisseck, I had never seen anything like this: the cavity was part of a crystallized bubble. The view went to the ceiling, where the best pieces are often found. Many fluorites had already dissolved and lay about 30 cm deeper in brown, sintered clay. Other pieces had loosened but were still attached to the ceiling. You could now easily “harvest” them. I managed to remain calm while enjoying this extraordinary sight. I could see many good pieces all within my reach. Of course, Toni and Michael had already noticed that it was suspiciously quiet in the cleft. When they called me, I was literally torn from my enchantment. My response was silent but eloquent: I handed out to them a nice sample of the treasures.

A nice fluorite from the new cavity

The surprise had the intended effect. I then gave them a brief report and crawled out so that Michael and Toni could also look at the cavity. Not surprisingly, for the next moments, perfect silence, as they then took in the extraordinary sight.

The front part of the new cavity with many fluorites at the bottom

Bad weather and thunderstorms delayed for six long days any further trips. Toni's vacation was now over, but Michael still had another week. Upon arrival at the site, we immediately noticed that parts of the unstable ceiling had collapsed due to the rain. We had previously decided to relieve the nappe by removing rubble above the cavity. Maybe we could even manage to get into the cleft from above? To remove debris and boulders above the cleft, we benefitted from the assistance from our new guests, Gerhard and Christian Aschacher, and Markus Hofmayr. They eagerly went to work while I ventured into the cavity to continue mining. Michael took the full buckets, cleared the rubble, and assisted when I needed something special. It took over two hours to remove this new debris from the ceiling to get back to the old level. Now we could again dig into "uncharted territory" and remove fluorite from the cavity. The rest of the day quickly passed as we engaged in what became a routine: clearing rubble, crushing boulders, removing stones, recovering fluorite, sorting, and finally packing up specimens. Several times in a two-week period, Toni came towards evening after work to pick up some of the “loot” which we packed for him. He quickly zipped up 1300 meters and then down again with 40 kg on his back. Quite a sporting feat.

Michael hands out a fluorite specimen. The facial expression was the same for all of us in such moments!

Two days later the five of us were on the road again. This would be our last trip to the Rucksack Cleft for the year. We aimed to close the cavity at the end of the day so that nobody would be tempted to crawl into a relatively unstable vault. The work continued above the cleft. Inside, we noticed some large boulders that were only loosely stuck in the cracked ceiling. A collapse while working in the cavity would be catastrophic, as that would make it almost impossible to get out through the narrow entrance. Again and again it trickled from the ceiling. After some rocks came loose, Michael climbed out from the cavity. He was no longer comfortable with such potential danger.  He watched with great uneasiness as I then climbed into the cleft to salvage more fluorite. I was very careful and tried not to touch any rocks on the ceiling. The effort proved worthwhile - I was able to salvage some nice pieces. I discovered a beautifully crystallized bubble with a diameter of approx. 70 cm on the side of the rock. These fluorites were located however in a particularly unstable area of the cavity. Here, of all places, the fluorite had grown and had to be pried off the rock. This work was really on the borderline of being reckless. Michael kept urging me to get out. But, foolish or not, I didn’t crawl out until I recovered some choice pieces. Now even I had to admit the danger was too great. The work above the cleft caused more and more rock to fall from the ceiling.  Of course, we had already  found more than enough fluorite for one day; our backpacks were once again well filled. After five successful tours we were finished for this year. We closed the cavity by loosening large boulders on the side and thus blocking the cleft entrance. The cleft should remain closed until next year. Grateful for our beautiful finds, the good fellowship, and happy that everything went well, we climbed back down into the valley.

In hindsight, the decision to invite various collector-friends to collaborate proved to be a good one. Some collectors were pleasantly surprised. For many, they could engage in a completely new experience because they had never before worked a fluorite cleft on Weisseck. All of our guests proved to be highly motivated and came with solid commitment to the task. We usually divided the finds of the day while we were still on the mountain; everyone could take as many pieces as they could or wanted to carry. The collaborations resulted also in renewing some old friendships.

While working, we were visited repeatedly by curious hikers. All the encounters were friendly. Interest in what we were doing was strong, sometimes resulting in long pleasant conversations. Many of the hikers were also very happy with surprise gifts in the form of fluorite from the famous Weisseck. In return some of them gave us sweets to provide us with some additional energy.

A side pocket with fluorite of excellent quality, edge length up to approx. 5 cm

One last look from the cleft for this year

The cleft is an approximately 60 degree standing and 1 meter wide fluorite-calcite stock that runs almost parallel to the ridge in the direction to the summit of Weisseck Mountain. In this area, the fluorite crystallized out with sharp edges and a maximum length of 3 cm. The fluorites were often overgrown with smaller unsightly corroded calcites. The quality of the fluorites in this area was generally not very good due to the proximity to the surface and the influence of water and frost. The quality was only better in protected areas. On the left side of the fluorite stock there was a cavity about three feet wide and five feet long. The exact dimensions could not be estimated at this time because we had only worked on the upper part of the cavity. The remaining part of the cavity was filled with rubble and lots of sinter-like rock. Fluorite of varying quality with an edge length of up to 5 cm had deposited on the side walls and ceiling. Many fluorites had detached from the ceiling as steps and lay on the floor.


The fluorites that we found reach a maximum edge length of 5 cm. Some pieces show a high-gloss crystal surface, but the majority has a matt shiny surface due to erosion. The faces of the cube are concavely bent inwards. Due to the concave cube shape, the parquet surfaces alternately shine in different areas as the piece is moved. The outer layer (1 to 3 mm) of fluorite is colorless to light grey. Inside is a sharp-edged purple phantom. With backlight, a very beautiful, intense violet to cardinal red color appears. The plastic and three-dimensional structure of the crystals is striking and characteristic of this cleft. Another feature of the site is the strong parquet structure and the pronounced edge growth. In some pieces, edge growth is so dominant that the individual cube is barely recognizable. A few fluorites show the dominant edge growth associated with a semicircular crystal structure. This combination gives the fluorite a flower-like character. These rare crystallized fluorites are a new species from Weisseck, which we particularly sought.

This piece shows all the characteristic features of the Rucksack Cleft: the clearly visible zonal structure with a lighter outer area, the intensive translucent color, the strong parquet structure and the intensive edge growth, which hardly allows the individual cubes to be seen, and in the upper area the semicircular like flower-shaped crystal structure, 12.5 x 7 x 5cm

In this photo, the strong parquet structure and the intensive edge growth, which hardly allows the individual cubes to be seen, are particularly evident, 12.5 x 7 x 5 cm

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Two generations of fluorite, the second generation is crystallized in the form of “sugar” and has partially overgrown the first generation

Bright transparent violet fluorite with an edge length of approx. 5 cm

Transparent violet fluorite with intensive square texture and high-gloss surfaces, 9.5 x 7 x 6.3 cm

Violet fluorite with intense square texture, inter-grown fluorite cubes and light gray zoning on one side, 9 x 7.3 x 5.9 cm

Intergrown fluorite cubes with an intense square texture and an intense violet translucent color, 9.5 x 8.5 x 4.4 cm

Transparent blue-green fluorite with an edge length of 5 cm, 6.5 x 5.5 x 4.5 cm

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In side view, the fluorite shows interesting green zoning and a violet center, 6.5 x 5.5 x 4.5 cm

Calcite was found partly in large masses as veins. It often occurs in combination with fluorite and can sometimes completely cover it. The maximum crystal size is about 2 centimeters. Many calcites were dissolved and unsightly due to the influence of water. In protected areas, the calcite shows a silky matt sheen. Small white baryte crystals - mostly in dome-shaped aggregates up to approx. 5 millimeters - occur occasionally between the fluorites and calcites. Sometimes the barite was surrounded by fluorite. Some fluorites were covered with a limonite-like layer.

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Transparent violet fluorite in combination with light calcite, 8.7 x 8.5 x 6 cm

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