They are deeply colored yellow to red to brown to black with diagnostic deeply colored streaks. Generally hard, but seem much softer due to the small grain size. Commonly forms radiating masses of crystals. They have glassy lusters and are transparent to translucent and are colorless to very lightly colored with white streaks. They are very soft.
Sulfide mineral tend to be metallic and deeply colored.
Commonly diagnostic brassy, grey or blackish metallic colors with disagnostic deeply colored streaks. You have trays that contain samples of the 13 important environmental minerals listed above. Spend the next 30 minutes looking at your mineral samples. The following exercises are designed to help you become familiar with these minerals and to help you learn how to identify them by their physical properties. List below sample number and two most diagnostic physical properties for each mineral.