Gaveznica – Kameni vrh

The Gaveznica-Kameni Vrh was legally protected on 18^th March 1998 as Croatia’s sixth geological natural monument. It is a site of semi-precious stone – agate – and the only preserved fossilised volcano in Croatia, and thus represents a scientific, educational and tourist landmark.

It was most active some 22 million years ago, and over time its cone has been washed away by the various seas that have risen and fallen during the geological history of this part of the planet. Gaveznica-Kameni Vrh is not only a fossil volcano, it is also an archaeological site on which remains of a prehistoric settlement dating from the Late Bronze Age have been found.

Lepoglava agate was formed in the cavities and cracks of andesite (the volcanic rock formed some 20 million years ago). It takes about 1000 years of quartz mineral depositing from mineral solutions inside rock cavities to produce agate.

Agate is a semi-precious stone whose chemical structure is quartz, i.e. silicon dioxide, and its name derives from its initial discovery near the River Dirillo (the Achate River) on Sicily.

Children’s workshops – panning for gold, making your own volcanic postcard and rock and minerals analysis under a microscope – are available along with a tour of the site.