In the past, the wine-growing region in the Thermen- & Vulkanland was called "Südoststeiermark", its new name is now "Vulkanland Steiermark", and that already says a lot. Because the soil is one of the special features of this area.

It has been a long time since the earth opened its floodgates. However, there are two periods that are responsible for the formation of the volcanic soils in eastern Styria. For example, the Gleichenberger Kogel and the Schaufelgraben in Bairisch Kölldorf were formed about 17 to 12 million years ago (Miocene). Traces of 40 volcanic vents can still be discovered today in southeastern Styria. They originate from the time of the younger volcanism (Pliocene and Pleistocene). For example, the Klöcher Massif was formed about 2.6 million years ago, the Stradener Kogel 1.71 million years ago and the Steinberg of Mühldorf 2.6 million years ago by major lava outpourings. Sometimes precious gems like olivines are enclosed in the tuffs. They can be found near Fehring, in Kapfenstein and around Feldbach. Olivines are representatives of the rock composition from a depth of 60 km.

Volcanic rock occurs in the Thermen- & Vulkanland in different forms, on the one hand as tuff, on the other hand as basalt. Tuff is, to put it simply, solidified igneous rock. That is, those parts that are thrown high into the air during a volcanic eruption. Tuff is coarse-pored and can still be hard, but also already so soft that it can be crumbled. Basalt, on the other hand, is cooled magma, i.e., liquid rock from the earth's interior that eventually cools after erupting. Basalt is dark gray to black, very compact and hard. There is still a basalt plant in Klöch today. Basalt is mainly used for the substructure of railroad tracks.