Lab # 2 The Study of Minerals Exercise #1 page 3 in text

What exactly is a mineral? There are 4000 naturally occurring minerals; only 150 are mined for economic reasons. See Pg. 18 for economic uses We can make any one of the 4000 minerals in the lab if needed or desired.

Minerals Are naturally occurring inorganic solids (without carbon). Can be made up of more the one element. Have a definite composition. Ex: Pyrite FeS All contain crystals Have a specific order of atoms called atomic structure. This gives the element specific physical properties.

Physical Properties They are used to identify one mineral from another. Each mineral has a unique set of properties called primary properties. Some minerals contain secondary or special properties.

Primary Properties All minerals have these properties. Luster – Metallic and Nonmetallic Hardness Streak Color Structure Cleavage Specific Gravity - also called Density

Not all minerals will have these properties. Special Properties Not all minerals will have these properties. Magnetic Feel Taste Smell Tenacity Reaction with Hydrochloric acid (HCl)

Metallic Vs. Nonmetallic Luster Luster - How minerals reflect light. Metallic – shiny like a metal # 10 Pyrite has a brassy color mined for Iron (Fe) and Sulfur (S) Used to make glass brown so used in making beer bottles. # 2 Galena PbS – ore of lead. Mined for lead (Pb)

Nonmetallic Luster Does not shine like a metal. #1 nonmetal glass luster. Rose Quartz. SiO2 # 7 non metal glassy luster. Talc mined and used in powder.

Hardness - Mohs scale Resistance of minerals to abrasion. Pg 7 in text Mohs scale Scale is 1-10 and all 4000 minerals fit in somewhere. Scale is not relative any mineral with a hardness of 5 is not 5 times stronger then a mineral with a hardness of 1. Everything from talc through diamonds (1-10).

3 Categories for Mohs Scale Less then 2.5 Between 2.5 and 5.5 Greater then 5.5 Our fingernail has a strength of this Stronger then our nail but not strong enough to scratch glass. Can scratch glass

Streak Powdered residue that a mineral will make on a porcelain plate. #11 Hematite Red/Brown (Pg. 5 – Fig 1.5) 2 types 1 red and one silver. Silver one used in jewelry making. Nonmetallic minerals usually do not streak. If the mineral is harder then the streak plate then no streak will be observed.

Color Virtually useless property. # 1 and # 13 are both quartz They both have the same composition, but the color change is from impurities. Color is the last property to be used for identification.

Specific Gravity (Density) The weight per unit volume. In English how much something weighs divided by its volume.

Today in Lab We will identify some of the minerals in our sets. We will fill in the identification charts on pages 11-13. Use the mineral identification keys on pages 14-16 for help to complete the data tables. Homework due next week: Complete the Summary Report on Page 19 -Ignore questions #2, 4 & 9

Special Properties # 5 Magnetite – Magnetic ; an ore of iron # 11 Hematite – Magnetic ; an ore of iron # 14 Graphite – Feels soapy or greasy Used as an industrial lubricant. # 19 Halite – Tastes like salt. (Taste if you want) # 26 Sulfur – Rotten eggs. Smell # 6 and 8 have Tenacity – ability to bend or flex # 12 Calcite – Reacts with HCl