Red soil
All our vineyards are located on red soil.
In the professional literature, red soil is known under the Italian name Terra Rossa (literally red soil).
This is a typical type of soil in Istria. It is characteristic of subtropical and Mediterranean karst regions or areas composed of limestone, which receive a significant amount of precipitation. Red soil has a red color, a large proportion of clay and a polyhedral structure. The soil is heavy, compacted and with little humus (1-3%). It was formed from the insoluble residue of limestone and dolomite in the process of the so-called rubification, and is formed along the bottom of sinkholes, valleys and karst fields. It contains oxides of iron and aluminum that give it a red color, after which it got its name. Based on previous research, a dozen pedological units of rubella (typical rubella, leached, feralitic, etc.) can be distinguished. Red soil is suitable for growing vines and fruits (figs, olives, etc.).
The largest areas (of about 90,000 ha) of arable red soil in the Republic of Croatia are located in the Istrian region, in the area of the western Istrian vineyards.
This is where the Visintin vineyards are located, on the deep Istrian red soil.
Sources:
https://hr.wikipedia.org/wiki/Crvenica
https://www.enciklopedija.hr/Natuknica.aspx?ID=61548

Red soil (terra rossa) in Croatia.
Image source: Goran Durn, „Terra Rossa in the Mediterranean Region: Parent Materials, Composition and Origin“, Geologia Croatica 56/1, Zagreb 2003 (https://core.ac.uk/reader/14378116).