How does luster and streak differ?

Minerals. A mineral, by definition, is any naturally (not manmade) occurring, inorganic (not a result of life plant or animal) substance. Its chemical structure can be exact, or can vary. All minerals belong to a chemical group, which represents their affiliation with certain elements or compounds. read more

Luster is the property of how light reflects off the surfaces of a mineral. Luster can be metallic (shiny and opaque like a metal: gold, pyrite, copper, silver), or nonmetallic (not shiny like a metal, or not shiny at all). read more

The most important are: luster, streak, hardness, and cleavage. It is also good to know a bit about such things as specific gravity, fusibility, mineral "habits", and the types of mineral "environments" different minerals are likely to be found in – what types of rock, under what physical conditions. read more