The streak is the colour of a mineral when it is finely powdered. You can easily test a mineral's streak. Simply scrape the mineral across the back of a white kitchen tile. The mark that is left on the tile is the streak.
Click on the tiles to the right and find out more about each streak.
Even if a mineral can be different colours, its streak will always be the same. This makes streak a particularly useful tool for identifying minerals.
Look at the example below. Both the specimens are a mineral called hematite. The one on the left is made up of metallic grey crystals. The one on the right is a dark red colour with a rounded shape. They look very different but they both have the same brownish red streak.
It is very important to remember not to test for streak on a good surface of your mineral - choose an edge where damage will not show too much.
To find out about minerals you should Take a closer look, and then find out about some of their properties...
Crystal shape Hardness
Cleavage and fracture Heaviness
Other tests What we have learnt
Return to the Detectives homepage, or finish by playing Mineral mastermind!