Classification of Meteorites
There are more than 50 meteorite types grouped into three broad categories: stony, iron, and stony-iron. Stony meteorites are further subdivided into chondrites and achondrites. Utah’s 18 known meteorites comprise 6 iron and 12 stony (11 chondrites and 1 achondrite) meteorites.
Stony meteorites generally resemble dark, heavy, clastic, sedimentary Earth sandstones or conglomerates. Chondrites contain spherical glassy particles called chondrules; achondrites do not. Chondrules may be the oldest material in the Solar System, about 4.5 billion years old, the age of the Solar System. Eighty-two percent of all the meteorites on Earth are chondrites and 7.8 percent are achondrites.
Iron meteorites are some of most distinctive meteorites because they have a metallic appearance, are very heavy, and usually have smooth depressions called regmaglypts on their surface that resemble “thumb prints.”
Stony-iron meteorites are mixtures of metallic iron-nickel and non-metallic materials.