玄武岩, or basalt, is a dark, fine-grained volcanic rock formed from the rapid cooling of lava. It is primarily composed of minerals like plagioclase, pyroxene, and olivine. Basalt is commonly found in oceanic crust and volcanic islands, making it one of the most abundant types of rock on Earth. This rock is known for its durability and strength, which makes it useful in construction and road building. Additionally, basalt can be used in various applications, including the production of rock wool for insulation and as a decorative stone in landscaping.