Why are some meteorites shiny inside?
Many meteorites contain iron-nickel metal. When they are cut and polished, the metal shines like silver.
From the outside, meteorites usually look dark and dull. But when scientists cut and polish them, many have shiny bits inside.
Metal flecks. Most stony meteorites contain small grains of iron-nickel metal scattered through them, like chocolate chips in a cookie. On a polished surface, these grains shine like tiny bits of silver. Some meteorites have lots of them, others only a few.
Iron meteorites. Iron meteorites are almost entirely metal. When cut and polished, they shine like a mirror. When a scientist treats the polished surface with a special chemical, a beautiful criss-cross pattern of metal crystals appears.
Bronze-coloured grains. Some meteorites also contain golden or bronze-coloured specks. These are usually a mineral called troilite, made of iron and sulfur.
Why is there metal in meteorites? Meteorites formed in space, where there was very little oxygen and water. On Earth, iron usually combines with oxygen to make rust or minerals. In space, iron could stay as shiny metal. That is one reason meteorites are special and why most Earth rocks do not have shiny metal grains inside.
On Earth. Once meteorites land, rain and air slowly rust the metal, so old meteorites may have brown, rusty spots instead of shiny ones.