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?