- Slides: 9
1 -2 Identifying Minerals 1. Classify Minerals using common mineral identification techniques. 2. Explain special properties of minerals.
Color • Color is not the best factor to use in identifying a mineral. • Impurities and weathering cause minerals to come in different colors.
Luster – The way lights reflects off a mineral’s surface. • Metallic – shiny like metal • Sub-metallic – shiny but not smooth looking. • Non-metallic – vitreous, silky, resinous, waxy, pearly, and earthy.
Streak – the color of a mineral in powdered form. • Rub a mineral against an unglazed porcelain tile (streak plate) • Streak color is a more reliable way to use color in identifying a mineral in some cases.
Cleavage Vs Fracture • Cleavage is the tendency for some minerals to break along flat surfaces. • Fracture is the tendency for some minerals to break unevenly along curved or irregular surfaces.
Hardness – a mineral’s resistance to being scratched. • Use Moh’s hardness scale where 1 is softest and 10 is hardest.
Density – The measure of how much matter there is in a given amount of space. • D = m/v • Water is 1 g/cm 3 • Specific gravity – the ratio of a mineral’s density to water’s • Gold is 19
Special Properties • Fluorescence – minerals glow under a black light. • Chemical Reaction – reacts with acid • Optical properties – when looking through a mineral the appearance changes • Taste – mineral has a distinctive taste. • Magnetism – mineral will attract iron objects. • Radioactivity – minerals that contain uranium or radium can be detected with a Geiger counter