VOLCANIC ROCK • DICTIONARY ONE.COM • Definition of Volcanic rock

... more care and attention. To begin with, the aspect of the vine garden influences the quality of the wine immensely. Then there is the soil. The best is the plastic clay (nyirok), which appears to be the product of the direct chemical decomposition of volcanic rock. This clay absorbs water but very slowly, and is, in short, the most favourable to the growth of the vine. As the vines are mostly on the steep hillsides, low walls are built to prevent the earth from being ...

— Round About the Carpathians • Andrew F. Crosse