In these
stony meteorites though, the two heavier oxygen isotopes show up in equal proportions.
Stony meteorites make up about 90% of the fallen rocks, and typically contain silicate minerals, molten cosmic dust balls, minerals and some metal.
Since one can't go about analyzing every rock,
stony meteorites are not recognized unless they are actually seen to fall or unless they land in areas where surface rocks do not occur.
Although this is a common type of
stony meteorite, such chondrites are rarely found, since they quickly weather to resemble terrestrial rocks.
Menke tentatively classified the 27-pound
stony meteorite as an ordinary chondrite and thus among the most common types recovered from falls.
This links it with the
stony meteorites, which are thought to be fragments from S-type asteroids broken off in collisions.
These dominate the inner asteroid belt and may be the source of the most common
stony meteorites we have in our museum collections, known as ordinary chondrites.
Meteorites have traditionally been divided into three broad categories:
stony meteorites are rocks, mainly composed of silicate minerals; iron meteorites that are largely composed of metallic iron-nickel; and, stony-iron meteorites that contain large amounts of both metallic and rocky material.
The most common are
stony meteorites, with iron-nickel metallic meteorites following.
Riches from on high Many of the precious metals mined today were delivered via a bombardment of
stony meteorites (illustrated above) that pummeled the Earth and left craters on the moon billions of years ago (SN: 10/8/11, p.
Another difference is that slag is a glassy material that shatters with the characteristic scalloped or "chonchoidal" fracture of glass while real
stony meteorites break more like terrestrial rocks.
Metal grains in
stony meteorites are a valuable clue because very few Earth rocks have them.
The meteorites recovered so far suggest that this object was an LL5-type ordinary chondrite, among the class of
stony meteorites with low iron content that are the most common to fall on Earth.
