1.  Labs 1 & 2 due TODAY  Check your blackboard for syllabus.  Will have office hours scheduled Wednesday morning!

3.  All minerals are Inorganic Naturally Occurring Characteristic Chemical Composition Distinctive Physical Properties Have a Crystalline Structure  More than 2000 different kinds of minerals have been identified  However only about 30 are considered common

5.  Minerals are analyzed for these common properties  Color  Crystal Form- reaction with acid  Luster- magnetism  Hardness - striations  Streak - specific gravity  Cleavage(Fig. 11)  Fracture  Be able to identify minerals in hand sample on the basis of their properties

6.  Most noticeable property  COLOR IS NOT ALWAYS DIAGNOSTIC  variety names  Ex: Quartz (SiO 2 ) can be Amethyst (purple), Citrine (orange), and numerous other varieties

8.  This is their body shape.  It is a reflection of the crystal structure and how the crystal grew.  habit  It is an EXTERNAL feature  It is common for crystals to crowd as they grow, forcing crystals to become intergrown and thus not display a crystal form.  Ex. aragonite, selenite

10.  How light reflects from the surface of an object  2 main types  Metallic  Non-metallic  Metallic luster minerals usually tarnish and weather to a non-metallic color, always observe a fresh surface (if available)

12.  resistance to scratching  Mohs Scale of Hardness  Hardness 1 to 10

14.  Can be VERY diagnostic  The color of a substance when in a powder  Scratch the mineral across a hard surface such as your streak plate.  Hardness of streak plate is 6.5

16.  Cleavage - the tendency of a mineral to break along flat parallel surfaces.  Tendency of crystalline materials to split along definite crystalographic structural planes. These planes of relative weakness are a result of the regular locations of atoms and ions in the crystal, which create smooth repeating surfaces that are visible both in the microscope and to the naked eye.  Quality of cleavage can be determined by reflectance of light.  Cleavage can be VERY DIAGNOSTIC of some minerals  Excellent, good, poor  Ex. Calcite v. Quartz  Fracture - Any break in a mineral that does not occur along a cleavage plane.  Fracture may be diagnostic  Uneven, splintery, hackly, conchoidal Ex. quartz

18.  Reaction to acid (HCL)  Fresh surface  Always reacts? Or only when powdered?  Calcite and dolomite  Striations  Straight “hairline” grooves on cleavage surfaces  Plagioclase feldspar and potassium feldspar Special properties

19.  Magnetism – influences some minerals containing iron. Hematite and Galena can be attracted to a magnet  Specific gravity – fancy way of describing density (basically it is density without units) Galena  Fluorescence Special properties

20. Minerals lab will conclude Tuesday, this week. Mineral Lab due Thursday, beginning of class. After Thursday 10% off/day