It is quite astonishing, if not a miracle: Now the extent of the “Bolzano quartz porphyry” is more than 6,000 km² with a calculated volume of more than 13,000 km³.
There are equally old and chemically identical rocks in the Valle Isarco in the area of the Trostburg, in the Val Sarentino (South Tyrol) and in mighty sequences also in the area between the Valsugana and the Cima d’Asta (Trentino). But geodes – Teiser balls (in german called “Teiser Kugeln”) – are only found in a few lava flows, solely in Teis! Their contents are true highlights from the depths; breathtakingly beautiful violet-coloured gemstones – better known as amethysts.

The eponymous work traces the story of a mineral hunter who sets out to find the coveted violet gemstone. He hammers and chisels at the hard andesite rock until he actually holds in his hands a teis sphere with wonderful amethyst crystals, which are even said to have spiritual powers.