NWA 3147 (Eucrite)Ībout 8% of the meteorites that fall on Earth are achondrites (meaning they do not contain chondrules), some of which are similar to terrestrial mafic igneous rocks. Chondrites are often considered to be “the building blocks of the planets”. Like comets, chondritic asteroids are some of the oldest and most primitive materials in the solar system.

Chondrites are typically about 4.55 billion years old and are thought to represent material from the asteroid belt that never formed into large bodies. Certain types of chondrites also contain small amounts of organic matter, including amino acids, and presolar grains. These particles, or chondrules, are composed mostly of silicate minerals that appear to have been melted while they were free-floating objects in space. Millbillillie (Eucrite)Ībout 86% of the meteorites that fall on Earth are chondrites, which are named for the small, round particles they contain. (2007) summarizes modern meteorite taxonomy. Modern classification of meteorites is complex, the review paper of Krot et al. Only 6% of meteorites are iron meteorites or a blend of rock and metal, the stony-iron meteorites. Most meteorites are stony meteorites, classed as chondrites and achondrites. Notice the Black Crust with faint flow lines & the different pale interior Modern classification schemes divide meteorites into groups according to their structure, chemical and isotopic composition and mineralogy. Meteorites have traditionally been divided into three broad categories: stony meteorites are rocks, mainly composed of silicate minerals iron meteorites are largely composed of metallic iron-nickel and, stony-iron meteorites contain large amounts of both metallic and rocky material. Sikhote-Alin - Strong regmaglypts with fresh blue/black fusion crust In contrast, there are over 38,660 well-documented meteorite finds. As of February 2010, there are approximately 1,086 witnessed falls having specimens in the world’s collections. Meteorites that are recovered after being observed as they transited the atmosphere or impacted the Earth are called falls. Meteorites have been found on the Moon and Mars. More generally, a meteorite on the surface of any celestial body is a natural object that has come from elsewhere in space. The term bolide refers to either an extraterrestrial body that collides with the Earth, or to an exceptionally bright, fireball-like meteor regardless of whether it ultimately impacts the surface. When a meteoroid enters the atmosphere, ram pressure (not friction) causes the body to heat up and emit light, thus forming a fireball, also known as a meteor or shooting/falling star.

Meteorite find in situ on desert pavement, Rub’ al Khali, Saudi Arabia. Most meteorites derive from small astronomical objects called meteoroids, but they are also sometimes produced by impacts of asteroids. A meteorite is a natural object originating in outer space that survives impact with the Earth’s surface.

Meteorite rock types