Diamond Mountain District AVA is in the Mayacamas Mountains at the northwestern end of Napa Valley. The appellation is relatively high and the entire district is more than 400 feet above sea level. Some vineyards are as high as 2,200 feet above sea level. Because of their altitude, Diamond Mountain vineyards experience warmer days but colder nights than vineyards on the valley floor. Once volcanic soil, the terrain in the appellation has over time become less fertile, making grape growing particularly challenging. Nevertheless the district has attracted wine producers for more than a century. There are 500 vineyard acres out of a total of 5,000 acres. Among the highly regarded wineries here are Lokoya Winery, Diamond Creek Vineyards and Schramsberg Vineyards. Diamond Mountain Cabernet Sauvignon and Cabernet Franc are generally firmly structured, rich and quite tannic. Chardonnay is full-bodied with apple and peach aromas and firm acidity.