There are three main types of plate boundary: divergent, convergent and transform. Plates move away from one another at divergent boundaries. This happens at mid-ocean ridges. Plates move towards one another at convergent boundaries; one plate is forced below another in a process called subduction.
The skin of a Concord grape is typically dark blue or purple, and often is covered with a lighter-coloured epicuticular wax bloom that can be rubbed off. It is a slip-skin variety, meaning that the skin is easily separated from the fruit. Concord grapes have large seeds and are highly aromatic.
Health Benefits of the Concord Grape (and Other Dark Purple Grapes). The Concord grape is the most popular grape variety in the United States. This dark purple cultivar belongs to the Vitis labrusca species (also known as Fox Grape), and its luscious fruits are commonly used to make both wine and grape juice.