Those that have lain on Earth s surface for long periods may be rusted almost beyond recognition. Despite many resemblances to natural rocks, minerals, slags and metals, meteorites usually possess a number of distinctive characteristics. However, some may not exhibit these characteristics and may require laboratory tests to confirm their identity. Specimens generally have a fusion crust, which is dull black to brown in colour, and quite soft. The crust is more prevalent on stones and stony-irons and may have partially flaked off.
Stones are the most abundant and resemble some terrestrial rocks, but are denser.
They contain scattered grains of metallic iron, that are visible on broken or polished surfaces, in a silicate matrix. These are generally visible to the naked eye in broken or cut specimens. Rare stony meteorites without chondrules are called achondrites. During atmospheric entry, only their surface is affected. Also they rust easily so that there may be no bright metal showing.