ROCKS AND MINERALS E J C H O N O U R S D A Y 2 0 1 3
DIFFERENCES BETWEEN ROCKS AND MINERALS MINERALS Solid formations that occur naturally in the earth Have a unique chemical composition Defined by its crystalline structure and shape ROCKS Solid combination of more than one mineral formation Can be composed of several minerals Can also contain organic remains and mineraloids Classified according to the process of its formation
TYPES OF ROCKS Igneous formed when molten lava solidifies after a volcanic eruption and is known to be rich in the mineral granite. Sedimentary formed from deposits of pre-existing rocks, pieces of onceliving organisms or chemical precipitation. Metamorphic formed by the transformation of one rock type to another, usually under great heat and pressure.
TYPES OF ROCKS Igneous Sedimentary Metamorphic Intrusive Clastic Foliated Extrusive Biologic Nonfoliated Chemical
IGNEOUS ROCKS
OBSIDIAN
GRANITE
PUMICE
RHYOLITE
ANDESITE
SEDIMENTARY ROCKS
COAL
LIMESTONE
ROCK SALT
SHALE
SANDSTONE
METAMORPHIC ROCKS
MARBLE
QUARTZITE
SLATE
AMPHIBOLITE
GNEISS
MOH S SCALE OF HARDNESS Most common method used to rank minerals according to hardness. Devised by German mineralogist Friedrich Moh in 1812. Moh s hardness refers to a mineral s ability to resist abrasion or scratching. A mineral with a given hardness rating will scratch other minerals of the same and lower hardness ratings.
MOH S HARDNESS SCALE Hardness Mineral Description 1 Talc Fingernail scratches it easily. 2 Gypsum Fingernail scratches it. 3 Calcite Copper penny scratches it. 4 Fluorite Steel knife scratches it easily. 5 Apatite Steel knife scratches it. 6 Feldspar Steel knife does not scratch it easily, but scratches glass. 7 Quartz Hardest common mineral. It scratches steel and glass easily. 8 Topaz Harder than any common mineral. 9 Corundum It scratches Topaz. 10 Diamond It is the hardest of all minerals.
IDENTIFYING MINERALS Some of the characteristics used to identify minerals are: Colour Luster Streak Cleavage Hardness Specific Gravity Texture Crystal
IDENTIFYING MINERALS COLOUR Although commonly used to describe a mineral, it is not a very good way of identifying a mineral. Some minerals are nearly always the same colour, but many come in a variety of colours. Some minerals change colour when the surface is exposed to moisture and air.
IDENTIFYING MINERALS LUSTER This is the way a mineral reflects light. Words used to describe luster Brilliant Dull Glassy Greasy Metallic Pearly Silky Example of Mineral Diamond Kaolinite Quartz Nepheline Pyrite Gypsum Kernite
IDENTIFYING MINERALS STREAK The colour of the powder a mineral produces when it is dragged across a hard, rough surface. For example, pyrite is a brassy, yellow colour, but it makes a greenish, black streak when rubbed across a rough surface.
IDENTIFYING MINERALS CLEAVAGE The tendency of minerals to break along definite planes, creating smooth surfaces. For example: Galena cleaves into little cubes Mica cleaves into thin sheets Calcite cleaves into slanting bricks Feldspar breaks into little steps Quartz cleaves into irregular chunks.
IDENTIFYING MINERALS SPECIFIC GRAVITY The relative weight of a mineral compared to an equal volume of water. The specific gravity determines the density of a mineral. Two different gems that are the same size can weigh different amounts. Specific Gravity Less than 3 Classification of Weight Light 3 5 Average At least 5 Heavy
IDENTIFYING MINERALS Texture The physical appearance or character of a rock, such as grain size, shape and arrangement. Crystal A solid whose atoms, molecules or ions are packed in a regularly ordered, repeating pattern. Snowflakes, diamonds, and common salt are common examples of crystals.
COMMON MINERALS AND THEIR PROPERTIES Name Colour Streak Luster Hardness Other Properties Graphite Black Black Metallic 1 Crystals are rare Mica Colourless White Pearly 2.5-3 Flakes into sheets Halite Colourless White Glassy 2.5 Salty taste Galena Gray Gray Metallic 2.5-3 Crystal Cubes Calcite Colourless White Glassy 3 Crystalline Magnetite Black Black Dull 5.5-6.5 Magnetic Pyrite Golden Black Metallic 6-6.5 Looks like gold Feldspar Various White Glassy 6-6.5 Two cleavages Quartz Various White Glassy 7 Round fracture Corundum Gray White Glassy 9 Crystalline
USES OF ROCKS AND MINERALS Rock Use Mineral Use Basalt Granite Road building materials Buildings, monuments and tombstones Quartz Diamond Marble Buildings, tiles Sapphire, Ruby Glass, electrical components and optical lenses Abrasives Lasers Obsidian Knives Copper Building construction, electric cables and wires, switches, alloys Pumice Scouring, scrubbing and polishing materials Feldspar Glass and ceramic industries, soaps, cement, fertilizer Slate Roofs, chalkboards Calcite Cements, mortars, production of lime Coal Fuel Graphite Pencil lead, lubricant Limestone Cement, paper, petrochemicals, insecticide, glass Gold Jewelry, arts, medicine, currency, scientific and electronic instruments
BIBLE INCIDENTS IN WHICH A ROCK WAS SIGNIFICANT Incident Text Ten Commandments Exodus 31:18 God commands Moses to strike a rock to provide the Israelites with water Numbers 20:2-13 David kills Goliath with a stone 1 Samuel 17 Jesus orders that the stone covering the tomb of Lazarus be removed John 11:38-44 Parable of wise and foolish builders Matthew 7:24-29 Stoning of Stephen Acts 6-7 Woman caught in adultery John 8:1-11
FOUNDATION STONES OF THE NEW JERASULEM These can be found in Revelation 21:19,20 and are listed below: Jasper Sapphire Chalcedony Emerald Sardonyx Sardius Chrysolyte Beryl Topaz Chrysoprasus Jacinth Amethyst.
SOURCES http://en.wikibooks.org/wiki/adventist_youth_honors_ans wer_book/nature/rocks_%26_minerals http://www.differencebetween.net/science/differencebetween-rocks-and-minerals/ http://geomaps.wr.usgs.gov/parks/rxmin/rock2.html http://geology.com/rocks.shtml http://chemistry.about.com/od/geochemistry/a/mohssc ale.htm http://library.thinkquest.org http://www.nma.org/publications/common_minerals.asp http://www.coaleducation.org/lessons/wim/20.htm http://www.rocksforkids.com/rfk/identification.html