lava
Some places inside Earth are so hot that rock melts. Melted rock inside the Earth is called magma. Magma can be hotter than 1,000 o C. When magma erupts onto Earths surface, it is known as lava Figure below . Minerals form when magma and lava cool. Some minerals crystallize at hotter temperatures. These minerals form first. Other minerals form at cooler temperatures. These minerals form later.