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The Importance of Mineralogy and Mineral Identification Skills

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Importance of Mineralogy List 5 things in this classroom that you think were mined?

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Importance of Mineralogy Almost everything except things that were grown (made from wood). Some surprising things that are mined: 1) Plastics all made from oil 2) Your clothing - half cotton (grown), half polymers or plastics (nylon, dacron, rayon, spandex - polymers made from petroleum). 3) Even the carpets and the drapes are made from polymer plastics. 4) Most cosmetics polymers. 5) The lead in your pencils actually Graphite 6) Salt yes, you are eating rocks! 7) Glass made from sand. 8) The chalkboard and the chalk. Chalk is made from pure limestone which is made from the skeletons of tiny ocean plankton. Let your English teacher know of the cruelty of smearing the skeletons of dead animals across the chalkboard every time chalk is used.

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Importance of Mineralogy The three most economically important groups of mineral resources are: 1) Fossil fuels (oil, coal and gas) 2) Aggregates (gravel, sand and cement) 3) Metal resources (iron, copper, gold, etc.) The mineral ores of copper All METAL resources come from mineral ores. Most of these metals come from impure forms sulfides, oxides, sulfates, carbonates, silicates, etc

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Importance of Mineralogy Hence the knowledge of minerals, their geological occurrence and their identification is the key to one of Canadas largest industries. The overall value of production of the Canadian mining, mineral- processing, and metal producing industries totals approximately $42 billion per year. Canada is now one of the largest mining nations in the world, producing more than 60 minerals and metals. The mining industry is a major player in Canada's economy and contributes nearly 5% of the country's Gross Domestic Product. Mining in Canada also accounts for 19% of the country's total exports.

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Importance of Mineralogy The mining industry provides Canadians with career opportunities. In 2007, the mining and mining processing industries directly employed 363,000 Canadians. And more skilled workers are needed. Current estimates indicate that the mining industry will need thousands of additional workers each year up to the year 2016! Canada ranks first in the world for the production of potash and uranium, and ranks in the top five for the production of nickel, cobalt, titanium concentrate, aluminum, magnesium and platinum group metals, gypsum, asbestos, cadmium, zinc, salt, molybdenum, and diamonds.

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Importance of Mineralogy In short, this data basically tells us that a degree in the Earth Sciences is the key to one of Canadas fastest growing, most well paid industries! Right now there are more jobs in the mining industry than Canadians with suitable qualifications. Excerpt from the Mining Association of Canada to the Competition Policy Review Panel (2006)

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Exploration Geology Since a vast array of products are produced from minerals, it is important that a geologist can identify one mineral from another. Today, I will introduce basic mineral identification skills and introduce the first few minerals from our mineral sets Next class, we will define what a mineral is and discuss mineral chemistry and crystal structure. Realgar (AsS) Gold nugget

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Mineral Sets and Testing Equipment 1) Take out the mineral sets and mineral test kits. 2) There are 30 minerals that you will need to know how to identify. 3) These minerals are chosen because they are either common or economically important. 4) There are over 3000 naturally occurring minerals but an average geologist might know how to identify 50 to 100 minerals. A mineralogy specialist might know a few hundred. 5) The first step in mineralogy is to know how to conduct the basic identification tests

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Mineral identification Labs In this course you will be expected to know how to identify about 30 common minerals and to know their chemical formulas. In order to identify these minerals, you will learn to use about 10 mineral identification tests. For each mineral that you learn in the lab, you will be given the data for some of the tests and will be conducting the tests to obtain some data for yourselves. When identifying minerals in the field or in the lab, it is only necessary to know two or three key pieces of information to make a positive identification.

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Mineral identification Labs A minerals physical properties are a result of their internal chemical structure. Silicate minerals tend to be hard because they have mostly covalent bonds and few ionic bonds. Similarly some minerals like Talc or Graphite are soft due to weak Van der Waals bonds. Many minerals have a high density due to a prevalence of heavy atoms. For example, Galena is very dense due to Pb atoms. A minerals crystal form is directly related to its atomic arrangement. Chemicals properties (such as reaction to acids) are directly related to a minerals chemical composition.

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Mineral Identification Tests Sight tests: 1) Colour 2) Crystal Form 3) Cleavage and Fracture 4) Lustre Physical Tests: 1) Hardness 2) Specific Gravity (Density) 3) Streak 4) Magnetism 5) Reaction to Acid Other tests such as taste, fluorescence and radioactivity are used in rare cases to identify some minerals. Mineral test equipment

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1) Colour Description The colour of minerals depends on the presence of certain atoms. Quartz can gain any colour due to chemical impurities. Testing method 1)Look at the sample and determine its colour - white, black, green, clear, etc. 2)COLOUR can be deceiving impurities in the mineral can change the colour of ANY mineral. As you can see below, quartz can be just about any colour! 5 colours of the mineral Quartz

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2) Crystal Form Description Geometric shape of a crystal or mineral. Testing method 1)Examine and describe the geometric shape of the mineral - cubic, hexagonal, etc. 2)Not all minerals display crystal form commonly in fact, crystal habit is rarely seen in most of the common rock forming minerals. 3)MASSIVE the term used to describe minerals that do not display crystal form

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The 6 Crystal Classes The shape of crystals is based on the internal symmetry of the crystals. All mineral crystals fall into one of these 6 or 7 classes. Examples of minerals and the crystal classes they belong to can be seen in the chart at right.

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3) Cleavage Description Breakage of a mineral along planes of weakness in the crystal structure. Cleavage is related to the crystal class of a mineral. Testing method 1)Examine the mineral for areas where the mineral is broken. Look for areas where the light reflects from planar surfaces. 2)This can be easily confused with a crystal face and is the most difficult properties for students to master. 3)Not all minerals show cleavage. Minerals with many cleavage planes tend to sparkle. blocky cleavage of feldspar perfect basal cleavage of mica

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Common types of Cleavage

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Fracture Description Breakage of a mineral, not along planes of weakness in the crystal structure. Testing method 1)Examine the mineral for areas where the mineral is broken. 2)Describe the breakage as either irregular or conchoidal (has the appearance of broken glass) The conchoidal fracture of quartz

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4) Lustre Description Character of the light reflected by a mineral. It is a measure of how shiny a mineral is. Testing method 1) Look at the sample to determine if the mineral is: metallic lustrous, looks like a metal non-metallic non-lustrous, dull, earthy sub-metallic displays a somewhat metallic appearance but tends to be duller. 2)Metallic minerals tend to be sulfides while sub-metallic minerals are generally oxides and some sulfides 3)Mineral books will list a wide variety of lustre terms that we do not need to know!

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Lustre Metallic Sub-Metallic Non-Metallic SphaleritePyrite Hematite Galena Talc Feldspar

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5) Hardness Description Resistance to scratching or abrasion. Put in other terms the ability of one mineral (or material) to scratch another. Testing method 1)Rate hardness based on the Mohs Hardness Scale. 2)Use your hardness testing kits to rate minerals as: very soft can be scratched with fingernail soft - too hard to scratch with fingernail but can be scratched easily with a nail. hard difficult to scratch with nail but cannot scratch glass very hard scratches glass 3) Only leave a scratch of 2 or 3 mm in length on a mineral!

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Mohs Hardness Scale 1) Talc 2) Gypsum fingernail = 2.5 3) Calcite old copper penny = 3.5 4) Fluorite 5) Apatite 6) Orthoclase (Feldspar) window glass or typical knife blade = 5.5 to 6.0 7) Quartz 8) Topaz 9) Corundum (Ruby/Sapphire) 10) Diamond The Mohs Hardness Scale is only relative. Meaning that fluorite at 4 is not twice as hard as gypsum at 2; nor is the difference between calcite and fluorite similar to the difference between corundum and diamond. An absolute hardness scale looks a little different than the relative scale. One word of caution for inexperienced collectors: do not SCRATCH NICE CRYSTAL FACES! A fractured, cleaved or inconspicuous part of the mineral should still give a good hardness test and not damage a potentially wonderful specimen.

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Mohs Hardness Scale The relation between the Moh's Scale and absolute hardness measured by other means is shown below:

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Hardness Scale Equipment Mineral Testing Kits will include a nail and glass plate for hardness testing. Place the glass plate on the table when testing hard minerals or else it may shatter in your hand! A 2-3 mm scratch is enough when using a pen knife/nail Fingernails have a hardness of 2.5. Any mineral that can be scratched by a fingernail is VERY SOFT If a mineral cannot be scratched by your fingernail but can be scratched by a knife or nail (5.5) it is SOFT If a mineral cannot be scratched by a knife/nail but cannot scratch a glass plate (5.5) it is HARD Any mineral that can scratch a glass plate is VERY HARD

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6) Specific Gravity (SG) or Density Description Density in g/cm 3 (water = 1). Ratio of the mass of a mineral to the mass of an equal volume of water. It is measure of how heavy a mineral is for its given volume. Testing method 1) Qualitative descriptions are generally used: light S.G. is less than 2.5 medium S.G. is between 2.5 and 3.5 heavy S.G. is between 3.5 and 5.0 very heavy S.G. is greater than 5.0 2) All metallic minerals are heavy so use comparative terms (example heavy for a non-metallic mineral)

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7) Streak Description Colour of the mineral when it is powdered. The colour produced when the mineral is scraped (streaked) across an unglazed porcelain tile. Testing method 1)Use this test only on metallic and sub- metallic minerals. 2)Grind a small amount of a mineral into a powder on a porcelain streak plate and determine the colour of the powder. 3)Unlike the hardness test, a larger more forceful test is OK. 4)Make sure you are streaking the correct mineral.

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8) Magnetism Description The electromagnetic force generated by a mineral Testing method 1)Use the magnet supplied in the Mineral Testing Kit and determine if a magnet is attracted to the sample. 2)Few minerals are magnetic (examples magnetite, pyrrhotite) and they tend to iron-bearing metallic minerals. Magnetite (Fe3O4) also known as lodestone

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9) Reaction to Acid Description Reaction of hydrochloric acid with carbonates particularly calcium carbonate (CaCO 3 ). Testing method 1)Using the acid dropper bottles supplied in the Mineral Testing Kits, place one small drop of HCl on a sample a watch for a reaction - effervescence (bubbles). 2)Wipe the sample with a tissue after the test. 3)Though the acid is relatively weak, use acid carefully!

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10) Other tests Taste This test is only useful when determining the presence of halite (NaCl) or potash (potassium salts). This test is not recommended for any other minerals due to the presence of toxic compounds, especially heavy metals. 5 colours of the mineral Quartz Radioactivity This test is conducted with a Geiger counter and is useful in identifying radioactive minerals such as Uraninite or Pitchblende (UO2) Fluorescence Some minerals fluoresce under ultraviolet (shortwave UVB) radiation. Minerals such as Scheelite (CaWO4) and diamond.

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Mineral Collection 1Quartz11Barite*21Galena 2Pyroxene*12Gypsum22Chalcopyrite 3Amphibole13Apatite*23Pyrrhotite * 4Talc14Calcite24Bornite* 5Biotite15Garnet25Graphite 6Muscovite16Hematite26Fluorite 7Phlogopite*17Magnetite27Halite 8Orthoclase18Corundum*28Malachite 9Plagioclase19Sphalerite29Chromite* 10Olivine*20Pyrite30Sodalite* * Do no teach these minerals if time is limited

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Silicates mineralformulamineralformula Quartz (1) SiO 2 (framework silicate) Orthoclase (8) (Feldspar) (3-D framework structure) KAlSi 3 O 8 Pyroxene (2) CaMgSi 2 O 6 (single chain silicate) Plagioclase (9) (Feldspar) (3-D framework structure) CaAl 2 Si 2 O 8 Amphibole (3) A 2 Z 5 Si 8 O 22 (OH) 2 or (double chain silicate) Olivine (10) (isolated silicon tetrahedrons) (Mg,Fe) 2 SiO 4 Talc (4) Mg 3 Si 4 O 10 (OH) 2 (sheet silicate) Garnet (15) (ring structure) A 3 Z 2 Si 3 O 12 Biotite (5) mafic mica (sheet silicate) Sodalite (30) Feldpathoid feldspar like structure Na 8 Al 6 Si 6 O 24 Cl 2 Muscovite (6) felsic mica (sheet silicate) Phlogopite (7) intemediate mica (sheet silicate)