 Describe physical properties used to identify minerals.  Identify minerals using physical properties such as hardness and streak.

 Mineral appearance Mineral appearance  Hardness Hardness  Luster Luster  Specific gravity Specific gravity  Streak Streak  Cleavage and fracture Cleavage and fracture

 What it looks like color  What color is it?  Which one of the following is gold? Identify by appearance.

 A measure of how easily a mineral can be scratched

Mohs Hardness Scale Mineral Talc Gypsum Calcite Fluorite Apatite Feldspar Quartz Topaz Corundum Diamond Rating 1Softest known mineral. It flakes easily when scratched by a fingernail. 2A fingernail can easily scratch it. 3A fingernail cannot scratch it, but a copper penny can. 4A steel knife can easily scratch it. 5A steel knife can scratch it. 6Cannot be scratched by a steel knife, but it can scratch window glass. 7Can scratch steel and hard glass easily. 8Can scratch quartz. 9Can scratch topaz. 10Hardest known mineral. Diamond can scratch all other substances. Testing Method

 The way a mineral reflects light is luster.  Luster is either metallic or nonmetallic.

 Specific gravity can be compared to density. compared  The specific gravity of a mineral is the ratio of its mass compared with the mass of an equal volume of water. 19.  Gold has specific gravity of times more dense  It means gold is 19 times more dense than water. Gold is 19 times heavier, 19 times more dense than water.

 When a mineral is rubbed across a piece of porcelain tile a streak of powdered mineral is left behind.

Cleavage is the way a mineral breaks along smooth, flat surfaces. Mica and calcite have cleavage.

 Minerals that break unevenly with rough or jagged surfaces have fracture.  Quartz has fracture. quartz

CLEAVAGE FRACTURE

 Gems (or gemstones) are highly prized minerals because they are rare and beautiful.  They are cut to sparkle.  Amethyst gets its purple color from a bit of iron.

 Cullinan diamond  Found in S. Africa in 1905  Largest uncut diamond ever found  Cut into 9 main stones and 96 smaller ones  Largest is called “Great Star of Africa.”  Belongs to the British monarchy.  Hope diamond  Most famous gem  Blue in color  Thought to be cursed  In the Smithsonian in Washington, DC

 Waste diamonds are used in industry as abrasives and embedded on cutting tools, such as saw blades and drill bits.  Quartz crystals are used in electronics and in timepieces. They vibrate and can control frequencies.  Rubies and emeralds are used in lasers.  Most industrial gems are synthetic, meaning manmade.

 Minerals are often found in ores.  Ores are minerals or rock that contains a useful substance AND can be mined at a profit.  Bauxite  Yields aluminum through smelting.  Smelting is a process where a rock is crushed and the metals are melted out of the rock.  Hematite and magnetite  Yield iron used in construction, cars, and many other applications where steel is needed.  Ilmenite and rutile  Yield titanium

 Some metallic elements can dissolve in fluids.  These fluids travel through cracks in rocks and form mineral deposits  These are called vein minerals.  Includes:  gold  silver  copper  zinc

 Titanium is used in  Auto body parts  Tennis rackets  Bicycles  Wheelchairs  Glasses frames  Replacement joints