Definition - What does Slate mean?
This is a metamorphic rock that is formed from compressed shale which is transformed under high pressure and temperature into a hard clay surface. Slate soils are used for planting vineyards due to its nutrient-dense and water retention properties that help vines grow in many different wine growing regions.
WineFrog explains Slate
As slate transforms from shale and clay into a harder rock, it is pushed to the surface, which helps the soils retain moisture and increases absorption of nutrients. The slate rock is also a beneficial conductor of temperature which absorbs the heat during the day and cools at night. The most notable vineyard sites are the Mosel and Nahe Valleys in Germany that are responsible for high-quality Rieslings due to the concentration of nutrients and the soil structure of slate. The rock cycle, weathering and crystallization of slates help the vineyard soils transform into new structures each year making them ideal for new vines growth and excellent fruit.