Date updated: 06/10/2023
Slovak opal mines

Not far from the town of Prešov in the area of Slanské vrchy (Slanské Mountains) between the village of Zlatá Baňa and Červenica is the mysterious underground world of the famous Slovak opal mines (Slovenske opalove bane). These are the oldest opal mines in the world known as Dubnické mines. Dubnícke mines were the only opal mines in the world until similar deposits were discovered in Mexico and Australia in the 19th century.
The Dubník mines have seventeen levels of tunnels and an extensive network of corridors that stretches for 35 kilometres, they were excavated by hand until 1922. After the mine closed in 1922, the five lowest levels were flooded.
Quick reference
Opal is a soft mineral rock that is formed as a result of the oxidation process of silicon. This rock usually has different shades, which change depending on the conditions in which it was formed. Opal can be white, transparent, grey, black or yellow as well as various shades of blue, green, pink and red. In addition to their beauty, opals also have a legendary reputation. In ancient times, opals were believed to bring good fortune and were able to foretell the future. In some cultures, opals were used to treat illnesses and strengthen the immune system.
Nowadays, opals continue to be in demand in the jewellery industry, where they are used to create jewellery of various shapes and sizes. In addition, opals are used in industry to make lasers, optical instruments and other high-tech devices.
Famous opals
Slovak opals are distinguished by their white colour, within which flashes of blue and orange can be seen, while the surface resembles a pristine untouched snowfield, which plays with multicoloured flashes of large snowflakes when the sunlight falls on it.
Hungarian opal
Photo courtesy of the Natural History Museum in Vienna
In 1775 one of the most famous and unique stones was discovered in Slovakia - the Harlequin opal, it was named after a character from a theatre comedy, another name is the Hungarian opal and it is under this name that it can be found in the Natural History Museum in Vienna. Weighing 2970 carats (594 grams) and measuring 13 x 7 x 7 cm, the precious Hungarian Opal is the largest precious opal ever found in Europe. The surface of the opal features a variety of multicoloured spots and flashes. The colour scheme includes blue, green, yellow, red and orange, which combine in a unique and unmistakable image.
Burning of Troy
"Burning of Troy" - one of the most mysterious gemstones in history. It is also one of the most elusive black opals. Opal gets its name from the special internal structure that creates the impression of flame on its surface. This bright red and intense glow on the opal's dark black background is reminiscent of the fierce flames that can be associated with burning Troy. The estimated weight of the 'Burning of Troy' is about 700 carats (140 grams). Until the 20th century historians believed that the opal came from the mines of the Dubnica mine, nowadays there are theories that the stone was mined in Honduras.
The story of this stone begins with Napoleon Bonaparte and his wife Josephine Beauharnais, whom he often lavished with expensive gifts, many of which were trophies of his military victories. One of the gifts was the Burning of Troy opal. There is currently no precise information about how it came to Napoleon, nor is there any information about the exact location of its extraction or the history of its transfer.
Josephine was passionate about jewellery and had a large collection of jewellery. "The Burning of Troy was one of her favourite stones and was considered one of the most valuable in her collection.
In 1814, after Josephine's death, the Burning of Troy opal disappeared and was long thought lost. One hundred years later, however, it suddenly appeared in Austria, where it was purchased by the city of Vienna. How the stone got to Austria remains a mystery. Officials of the city government valued it so highly that even during the period of financial difficulties after World War I, they refused to sell it. However, at the start of the Second World War, the 'Burn of Troy' disappeared again and to this day its whereabouts are unknown. Unfortunately, there are no photographs or drawings of the (supposed) 700 carat stone, but there is plenty of information about it in the historical record.
Excursions
Entrance to the Jozef tunnel
Slovakia's opal mine opened its doors to tourists in the summer of 2015. It was renovated to make it safe for visitors and now offers a guided tour of one of the main entrances to the underground opal mines, the Józef tunnel. Artificial lighting, stairs and walkways have been added inside the mine to allow easy passage through the underground spaces with a minimum of effort.
A tour of the 1,280-metre-long opal mines will take tourists about 45-60 minutes. The entrance and exit are at the same height, making it easy for all groups of visitors to get around. The temperature in the mines ranges from +4°C to +6°C throughout the year, so tourists should prepare accordingly.
One of the main advantages of visiting the opal mine is the opportunity to see various samples of opals and other minerals as well as rare types of crystals. Visitors can also look at antique miners' lamps, carts and tools used in the mine 100-150 years ago.
Extreme tour
If you want to experience a real adventure... For four hours, you'll immerse yourself in history and explore 35 kilometres of corridors in an underground opal mine. You can try your hand at mining this rare gemstone using the same tools that miners used 100-150 years ago. Such an adventure will enable you to better understand the difficulties faced by miners of that time. A total immersion in the atmosphere of the miners of that time. Don't miss your chance to become a true treasure hunter and embark on an unforgettable underground adventure!