The Varaždin region, today a symbol of green hills, stunning views and vineyards, was once – or, as Mother Earth might say, more recently in her own timeline – a land of fire! Did you know that millions of years ago this area was volcanically very active?
The only preserved volcano in Croatia – and the country’s only site of semi-precious gemstones – lies near the town of Lepoglava. This location, known as “Gaveznica – Kameni vrh”, stands 373 metres high and has been a protected geological natural monument since 1998. Today, a large quarry pit marks the site, hiding from the untrained eye the fact that a fossil volcano once stood here, most active around 22 million years ago.
It is called a fossil volcano because it was soon covered by younger sediment layers after its formation and re-exposed only about two million years ago during the Upper Pliocene. Over millions of years, seas that came and went sculpted its distinctive shape throughout the geological evolution of this part of the planet.
The former quarry is now a place of great interest for its semi-precious minerals such as agate, opal, and chalcedony. These mineral formations were created during the later phases of volcanic activity when hydrothermal processes affected the volcanic rocks, giving rise to the beautiful Lepoglava Agate.
Agates formed in the cavities and cracks of andesite rock, about 20 million years old. It takes up to a thousand years for just one specimen to form, as quartz layers slowly deposit within the rock – a true natural wonder unfolding deep beneath the present-day Varaždin region.
It is believed that the Pauline monks were well acquainted with this site in the Middle Ages, and there are indications it was used even earlier. Evidence suggests that Stone Age people also recognized the area’s value. In the Vindija Cave and the Great Cave on Ravna Gora, stone knives, scrapers, axes, and other tools have been found, showing advanced prehistoric stone processing. Particularly interesting are green tuff hand axes from Vindija, indicating that ancient inhabitants already appreciated this local material.
Recently, new deposits of semi-precious stones have been discovered near Čret, about 4 km east of Gaveznica, including various forms of chalcedony, red jasper, and agate, with rarer finds of amethyst and opal.
Lepoglava is also linked to mineralogy through lexicographer Ivan Belostenec, whose Gazophylacium (1740) includes about 270 mineralogical terms and laid the foundation of Croatian mineralogical terminology.
The Gaveznica – Kameni vrh site was first described in 1936 by Stjepan Vuković, and traces of a prehistoric Bronze Age settlement have been found on its summit.
Today, although the area no longer holds commercial significance for agate exploitation, it has great educational, scientific, and tourist value. Gaveznica – Kameni vrh has become an educational trail that tells a story millions of years old, offering visitors a unique encounter with the geological past of our planet.
Come, explore, and feel the breath of the ancient volcano!
Walk along the Gaveznica educational trail, touch rocks millions of years old, and discover where the Lepoglava Agate hides – a jewel preserving the story of fire, time, and nature.
Visit Lepoglava and travel through the geological history of the Varaždin region – the land of volcanoes! Choose your accommodation on our website and begin your journey through this unique natural treasure.