2 All minerals are rocks, but not all rocks are minerals! Minerals vs. RocksRock – an aggregate of minerals (mixture of minerals).Mineral – naturally occurring, inorganic, crystalline solids, with a definite chemical composition.All minerals are rocks, but not all rocks are minerals!
6 Properties of Minerals 2. LusterAppearance /quality of light reflected from the surface of a mineral.Metallic vs. Nonmetallic.
7 Choosing the Luster: Luster Shiny like a metal? Yes Metallic No NonmetallicWhat kind of nonmetallic?Vitreous(glassy)PearlySilkyResinousEarthy
8 Properties of Minerals 3. ColorOuter appearance.Unreliable property.A mineral may have several color varieties.
9 Properties of Minerals 4. StreakColor of the mineral in a powdered form.Obtained by rubbing the mineral across a streak plate.
10 Properties of Minerals 5. HardnessResistance to abrasion or scratching.Mohs’ ScaleTalcGypsumCalciteFluoriteApatiteFeldsparQuartzTopazCorundumDiamondSoftestHardest
11 How to test a mineral’s hardness Start by moving an unknown sample across a sample with a hardness of 1.2. If the unknown scratches the known sample, then it is harder….so keep testing the others until it doesn’t scratch it.3. If it doesn’t scratch it, then it is softer than the known sample so it is lower on the scale.4. If they scratch each other, they are the same hardness.
12 Properties of Minerals 6. CleavageTendency for a mineral to break along planes of weak bonding.Smooth surfaces.Not to be confused with crystals.
13 Properties of Minerals 7. FractureOpposite of cleavage.Conchoidal fracture = curved edges.Fibrous fracture = splinters/fibers.
14 Properties of Minerals 8. Specific GravityComparison between the weight of a mineral to the weight of an equal volume of water.Comparison of densities.Written as the number of times heavier/lighter than water.
15 Properties of Minerals 9. Other PropertiesTasteElasticityMalleabilityTextureMagnetismDouble RefractionReaction to acids (HCl)
16 Mineral Groups O Si Al Fe Ca Na K Mg 8 elements make up 98% of the Earth’s crust (by weight).OSiAlFeCaNaKMg
17 Mineral Groups Silicate Group Minerals made of O and Si. ¾ of the minerals in the continental crust are silicates.Silicon-oxygen tetrahedron (1 silicon to 4 oxygen) then bonded to another element(s).EXAMPLES:Quartz, Feldspars, Micas
18 Mineral Groups Carbonates Group Halides Group Minerals made of CO3 bonded with other elements.EXAMPLES:Calcite & DolomiteHalides GroupMinerals made with members of the halogen family.Formed through evaporation.Halite & Fluorite
19 Mineral Groups Sulfates Group Oxides Group Minerals made of SO4 bonded with other elements.EXAMPLES:GypsumOxides GroupMinerals made with Oxygen bonded with other elements.Hematite & Ice
20 Mineral Groups Native Elements Group Sulfides Group Minerals that are pure elements (usually metals).EXAMPLES:Copper, Diamond, GraphiteSulfides GroupMinerals made with Sulfur bonded with other elements.Pyrite
21 Mineral ResourcesOres – useful metallic minerals that are mined at a profit.EXAMPLES: Hematite (Iron), Sphalerite (Zinc), Galena (Lead), Cinnabar (Mercury).Industrial rocks & minerals – useful nonmetallic minerals that are mined at a profit.EXAMPLES: Fluorite, Sulfur, Halite (salt)The amount of a mineral in a deposit must be concentrated several times it’s crustal percentage to be considered profitable.
22 Mineral ResourcesGemstones – Crystal forms of minerals that posses beauty of such quality that command a price when cut & polished.Precious gems – have beauty, durability, size, and rarity.DiamondEmerald (Beryl)Ruby (Corundum)Sapphire (Corundum)
23 Mineral ResourcesSemiprecious gems – only have one or two of the qualities of precious gems.EXAMPLES: Amethyst , Topaz, Garnet, ZirconNon-mineral gems – stones that have value, but are not minerals.EXAMPLES: Coral, Amber, PearlPrecious Metals – metallic minerals that have high value.EXAMPLES: Gold, Silver, Platinum