China has six main types of tea: 绿茶 (green), 红茶 (black/red), 白茶 (white), 黄茶 (yellow), 乌龙茶 (oolong), and 黑茶 (dark). Fujian and Yunnan are the most famous tea regions.
usage
茶叶 refers to the physical leaves or the product you buy. 茶 alone means either the drink or the leaves. When buying tea, you ask for 茶叶; when drinking, you ask for 茶.