A meteorite composed primarily of silicate minerals, usually with some nickel-iron; also known as an aerolite. Around 95% of all meteorites observed to fall are stones. However, they are difficult to distinguish from terrestrial rocks, and many go unnoticed. Their fusion crust is thicker than that of irons and is often black in colour, either dull or shiny. The interior of stones is usually grey or dark grey, and granular in texture. Stony meteorites are divided into two main subtypes: chondrites, which comprise 82% of all observed falls, and achondrites.