IN: If you had to describe how one mineral is different from another, how might you describe its properties?

3-2 IDENTIFYING MINERALS3-2 IDENTIFYING MINERALS

How are these two minerals are the same? How are they different?

PROPERTIES OF MINERALSPROPERTIES OF MINERALS

Color Luster Streak Cleavage and Fracture Hardness Density Special Properties

COLORCOLOR The same mineral can come in different colors. Impurities

Quartz-white, red, pink, and purple Weathering

Pyrite turns black Color is not a very reliable indicator of

a mineral’s identity.

LUSTERLUSTER The way a surface reflects light. (How it

Shines)

There are 3 types:1. Metallic2. Submetallic3. Nonmetallic (vitreous, silky, resinous, waxy,Pearly or Earthy)

METALLIC LUSTERMETALLIC LUSTER

Looks shiny, like metal.

NONMETALLIC LUSTERNONMETALLIC LUSTER

Does not look like metal.

Vitreous quartzPearly talc Earthy psilomelane

Has properties of both metallic and nonmetallic.

Hematite

STREAKSTREAK The color of a mineral in a powdered form. (shows its “true color”)

The color of a mineral is not always the color of its streak.

STREAKSTREAK

A minerals streak is not affected by weathering.

Therefore, a mineral’s streak is much more reliable than its color.

CLEAVAGECLEAVAGE

The tendency of some minerals to break along flat surfaces.

FRACTUREFRACTURE

The tendency of some minerals to break unevenly along curved or irregular surfaces.

HARDNESSHARDNESS

A mineral’s resistance to being scratched.

DENSITYDENSITY The measure of how much matter there is in a given amount of space.

Remember the density of water=1g/mL

Properties that are particular to only a few types of minerals.

SPECIAL PROPERTIESSPECIAL PROPERTIES

Fluorescence

CHEMICAL REACTIONCHEMICAL REACTION

Calcite will “fizz” with acid

OPTICAL PROPERTIESOPTICAL PROPERTIES

RADIOACTIVITYRADIOACTIVITY

Uranium

MAGNETISMMAGNETISM

Magnetite

TASTETASTE

Halite Tastes “salty”

OUT: How would you summarize the seven properties of a mineral?