Mineral collecting in Slovakia
Trevor Devon (UK)
Slovakia is situated at the north-western end of the Carpathian Mountains, a region well-known for its metal ore mines and quarries. One of the Sussex Mineralogical Society’s members had been a schoolteacher in Slovakia and had explored many of its mineral locations. Through his contacts there, an 11 day visit was arranged and a quite large group, comprising 17 society members, descended on the rural tranquillity of eastern Slovakia in August 2008. We were met by our two expert guides, one of whom was Dr Rudolf Ďud’a, head of the Department of Natural History in the Eastern Slovak Museum in Košice and author of the Slovakia chapter in the book Minerals of the Carpathians.
Our journey took us on a round trip from eastern Slovakia up to Prešov and the Tatra Mountains on the border with Poland, across to Banská Bystrica in central Slovakia, south to šiatorská Bukovinka near the Hungarian border and back to Košice. Much of the driving was through heavily wooded mountains and attractive scenic valleys. The mines (now mostly inactive) and quarries were often well hidden, and generally required some walking (always upwards, of course) to get to from our coach.
During our trip, we visited four quarries, eight mine dumps and a wooded mountainside deposit of ‘flesh opals’, so we were kept busy. One of the lasting impressions of the mine dumps (some of which were very large indeed) was the richness of secondary mineralisation – when in Cornwall, one is usually excited by any tiny piece of blue or green on the rock. In the Slovakian mine dumps, we saw seas of green/blue mineralisation. However, closer inspection revealed much of it to be microcrystalline crusts, which we were happy to discard, while looking for the real crystalline specimens.
In fact, I came home with a lot of small, but fine specimens of many of the copper secondaries, such as azurite, malachite, brochantite, chalcophyllite, liroconite, cornubite, tyrolite, chrysocolla and cornwallite. Others collected some good crystals of the famous euchroite from L’ubietová (the type location). Unfortunately, while we were at L’ubietová (Libethen in German), we did not manage to get to the area famous (as the type location) for libethenite, so I bought a nice specimen from a local dealer instead.
In addition to the copper secondaries, the mine dumps yielded many of the metal sulphides, notably crystals of chalcopyrite, pyrite, bornite, marcasite, metastibnite, tennantite, realgar, sphalerite and tetrahedrite. However, despite visiting a former gold mine dump, no gold was found. At one location, the group split into two – the fit and adventurous went up a 2km steep path to a mine dump, while the rest (including me) stayed down below exploring the track that had been constructed from mine dump rock. Needless to say, we collected much the same minerals at the bottom as they found at the top (although, truth to say, the top group did find larger crystals). Most of us found the rare lead-antimony sulphide, tintinaite, which appears in the quartz rock as dark acicular crystals, up to 10mm long.
Quarries are usually a particularly good source of mineral specimens for the collector, as fresh material can often be uncovered, either by excavation of an evident mineral seam or through quarrying, if the location is still active. We were not to be disappointed by the four different quarries we visited. The first, called Vechec Lom (‘lom’ means quarry), was a large active andesite quarry, from which we extracted many good hand specimens of the high temperature quartz crystal polymorphs tridymite and cristobalite (the reason they can still be found naturally is because their breakdown to quartz takes place very slowly). And, one geological feature of Vechec was a spectacular outcrop of large hexagonal andesite columns (Figs. 1 and 2), so now I don’t need to visit the Giant’s Causeway or Fingals Cave.
Our second quarry, Maglovec Lom, was also an andesite quarry and is well known mineralogically for its pale green chabazite, which is a zeolite mineral. We did find plenty of the chabazite, but much of it was present as filler in cracks between andesite blocks. However, some good hand specimens of rhombohedral crystals were extracted. Of some interest too were the unusual sheets of material forming thin layers on the surface of the chabazite. In fact, the fine fibrous material was a magnesium silicate mineral palygorskite, known as ‘mountain leather’.
The third quarry at Dobšiná was quite different, being an asbestos quarry. The matrix rock was serpentine and the asbestos could easily be found as layers of golden fibrous clinochrysotile. Yellow-green specimens of the magnesium silicates antigorite and lizardite were commonly found along with the asbestos. Also at this location, several small specimens of bright grass-green crystals were uncovered by cracking open small boulders. These were a variety of andradite garnet known as demantoid (meaning ‘diamond-like’, because of their adamantine lustre).
The final quarry near the Hungarian border, šiatorská Bukovinka, was a working andesite quarry. We could not get to the base of the quarry because of the active machinery, but we nevertheless found plenty to interest us on the higher benches. First finds were zeolites: lots of white, chalky prisms of laumontite crystals (to 10mm) and white radial sprays of scolecite. These were sometimes accompanied by an unusual, platy form of apophyllite. Higher up in the quarry, one of our colleagues uncovered a horde of the rare zeolite, epistilbite, in a cavity in the quarry wall. Fortunately, there was enough for everyone to have a good specimen of these crystals. I was also fortunate in finding, on my way down the quarry, some really nice specimens of chabazite that had been extracted earlier by persons unknown and left on a rock.
Mention should be made of the other form of mineral collecting, that is, by cheque book. We did meet up with several collectors/dealers during our trip and several of us supplemented our finds with purchased specimens from Slovakia that we either hadn’t found or were better examples of what we had found. In this way, I acquired some representative crystalline specimens of euchroite, libethenite and langite.
On our last day, we drove back to Košice, where Dr Ďud’a arranged a tour of his natural history department at the Eastern Slavic Museum. This turned out to be really quite exceptional – bright, clearly laid out modern displays, with a wide range of local and world minerals. We were also treated to a visit to a unique exhibit, displayed inside a double vault, of the Košice Horde – a priceless treasury of medieval gold coins that had been hidden over the centuries from various invaders and were returned to Košice in 1970. A pleasant walk around this city before lunch revealed some magnificent architecture that suggested a return trip one day. Then, after lunch, we repaired to the home of Dr Ďud’a to see his amazing mineral collection displays (he has amassed over 3,500 different species of mineral). As a further treat, we were offered boxes of his duplicate minerals from which to select free specimens. And, it was at about this stage that we started to think about our luggage allowances…