Stones constitute the largest group of meteorites. They originated in the outer crust of a planet or asteroid. Visible inside most stone meteorites are tiny, glassy, spheres known as chondrules. Forged at the very dawn of the solar system, these chondrules are far older than our own planet. Some stone meteorites, known as carbonaceous chondrites, have been found to contain water, salt, and even amino acids. In the distant past, these meteorites may have carried the very building blocks of life to Earth!