12 MINERAL IDENTIFICATION KEYThe lab manual goes through the steps that are needed to be completed for each diagnostic test (color, hardness, acid, etc.) that you are performing on all your samples. You will collect and record your data on figure 1.23, page 14. There is a mineral ID key located on pages 16 – 18 in your lab manual (Applications and Investigations). Once you have completed all of your diagnostic tests on your samples try and match up as many of the properties of your samples to the properties of the known minerals (names for the known minerals are in the yellow box in the ID key. The tutor can check your answers for you if you like. You can send him/her an email with your sample number and your proposed name (i. e. M99 = diamond). The information you collect may be needed to answer several questions of the lab report on pages 23 and 24. NOTE: If one or two properties of your unknown samples do not match up with what you think is the known mineral, yet the remaining dozen properties do match, chances are you have correctly identified that mineral. NOTE: Online students should write down the sample names and numbers at the bottom of the SRP. 13 UNKNOWN MINERAL SAMPLES – SUMMER 2021 If you do not have your lab kit, you may use these samples for lab exercise 1. Use your mineral chart to fill in properties (color, luster, etc.) of the following unknown minerals. None of these samples are magnetic. Some special properties may be listed below each specimen to help you. Mineral Sample M1 • • • • • Note the tarnish Can be hammered or shaped Hardness: 2.5 – 5.5 Copper streak. Density about 9 g/ml 14 Minerals Sample M2 • • • • • • • • • This sample would fracture conchoidally. No cleavage. This sample is pink, but it comes in a wide variety of colors. Scratches glass easily. Does not have metallic luster although it looks shiny. Does not bend. Density approximately 3 g/ml. Hardness: greater than 5.5. (scratches glass) Opaque or at times translucent. 15 Mineral Sample M3 • • • • • • • This sample is transparent. Does not bend. Is not brittle. Reacts positively to hydrochloric acid. May be colorless, white, or pale yellow. Hardness: 2.5 – 5.5. Smooth texture. 3 directions of cleavage @ 750 16 Mineral Sample M4 • • • • • • • This sample is yellow in color. Rotten egg smell. Fractures. Splinters at times. Does not bend. Opaque. Non-metallic luster. 17 Mineral Sample M5 • • • • • • • • This sample is not transparent. Does not bend. Is not brittle. Could be made into sheets. Can be molded and hammered. Yellow color. May slightly smell like rotten eggs. Metallic luster. Density: about 5 g/ml. Hardness: greater than 5.5. 3 directions of cleavage @ 900 18 Mineral Sample M6 • • • • • • • • This sample is transparent except if it very thin. Does bend and can be brittle. Reacts negatively to hydrochloric acid. May be black, brown or both. Look shiny but is not metallic in luster. Hardness: 2.5 – 5.5. Smooth texture. 1 direction of cleavage (basal, sheet) 19 Mineral Sample M7 • • • • • • • • • This sample may be opaque, translucent, or transparent. Does not bend. Is not brittle. Reacts negatively to hydrochloric acid. May be colorless or white. Hardness: 2.5 – 5.5. Salty taste. Smooth texture. Non-metallic luster. 3 directions of cleavage @ 900 20 MINERAL PROPERTIES CHART: Fill in the data chart with the information provided in the unknown mineral sample descriptions. This chart can be used in place of lab manual page 14. You may fill in your sample numbers (from the lab kit samples) and remove the others if you want to use this table. SAMPLE OPTICS COLOR STREAK CLEAVAGE FRACTURE TASTE ODOR TEXTURE HARDNESS # m99 opaque black black no yes no none rough > 5.5 M1 M2 M3 M4 M5 M6 M7 SAMPLE TENACITY- TENACITY- TENACITY- LUSTER MAGNETIC ACID MASS VOLUME DENSITY # ELASTIC BRITTLE MALLEABLE REACTION m99 no no no metallic yes no 52.0 10 ml 5.2 g/ml g M1 M2 M3 M4 M5 M6 M7 21 IDENTIFICATION KEYS/CHARTS: Using the Mineral Data Chart and the ID Keys, identify the name of the unknown samples. Sample M99 is depicted below. 22 23 24 Once your unknown mineral sample is identified, you must determine its use. 25 SAMPLE # m99 MINERAL NAME magnetite MINERAL USE mined for iron M1 M2 M3 M4 M5 M6 M7 26 LAB 1 (THE STUDY OF MINERALS) SUPPLEMENTAL LAB PACKET REPORT PAGES You may submit this in place of the lab manual lab report (pages 23 and 24) if you do not have your lab kit. Name: ________________________________ Section: _____________ Date: _______ 1) Check off the box of the mineral samples exhibiting metallic luster. 2) Complete the following table: SAMPLE MATERIAL IS THIS A MINERAL? YES OR NO. RATIONALE RAINWATER SYNTHETIC RUBIES NATURAL GAS GOLD WOOD PLASTIC HALITE QUARTZ ICE WOOL 27 3) With the data you gathered along with using the identification keys/charts, list the unknown mineral samples name and economic use: SAMPLE # M99 MINERAL NAME magnetite MINERAL USE mined for iron M1 M2 M3 M4 M5 M6 M7 4) Which sample below, A or B, is harder? _______ 5) Describe the cleavage pattern (if applicable) of each mineral sample listed below. Fill in the table. MINERAL SULFUR TALC GYPSUM FLOURITE CALCITE BIOTITE HALITE QUARTZ POTASSIUM FELDSPAR KAOLINITE CLEAVAGE PATTERN OR FRACTURE 28 6) List a special property associated with each mineral. Fill in the table. MINERAL GRAPHITE SPHALERITE MAGNETITE FLOURITE CALCITE MUSCOVITE HALITE GALENA POTASSIUM FELDSPAR KAOLINITE SPECIAL PROPERTY 7) A mineral sample scratches your fingernail but not a glass plate. How would you describe the mineral’s hardness? _______________________________________________________________ 8) Using the mineral identification charts, name the mineral sample pictured below. _____________________________________________________ 9) List the two most common rock-forming silicate mineral groups. ______________________________________________________________ 10) What is the best term to use to describe the tenacity of muscovite? ______________________________________________________________ 29 Atlantic Cape Community College Earth Science- ESCI100 Minerals Background: Mineral – a naturally occurring, inorganic solid that has unique chemical and physical properties. Minerals are the backbone of rocks. Rocks comprise the very solid Earth we stand on. Minerals are also obtained for use in many commercial, industrial, and medical products that we use. Much of this was discussed in the Matter and Minerals chapter of the textbook. Materials: Online students will have three unknown mineral samples labeled M#. The three unknown samples are representative of a metallic mineral, a dark non-metallic mineral, and a light non-metallic mineral. In addition, the kit should also include black and white porcelain streak plates, a small magnet, a glass plate, a goniometer, and a magnifying glass. If the magnifying glass is not in the kit, you can use the stereoscope. Students should have access to some white vinegar (to substitute for hydrochloric acid), a penny (copper strip) and a paper clip. All lab kit materials should be kept away from children. Suggestions: Students will perform diagnostic tests on mineral samples, compare your results to known properties listed on the Mineral ID Key and then make an educated guess as to the name of your mineral specimens. There will be different minerals assigned. Part of your grade is based on the correct identification of unknowns. You must post your findings (EX: M99 = gold) in the Minerals lab discussion board. 1 Mineral lab precautions: HANDLING: If you have a possible allergic reaction to materials such as talc or sulfur, it is best to wear gloves when handling samples. ACID TEST PRECAUTIONS: Use caution when handling the vinegar (acetic acid). Use only a few drops. Goggles and gloves are worn when using acetic acid (vinegar). Perform the acid test in a well-ventilated area. If you have mineral sample M16, perform the acid test on it. All others will be considered acid negative will be considered acid negative (-) and are not carbonates. HARDNESS TEST PRECAUTIONS: Use caution when handling glass plates. Do not try and rub a mineral sample with the glass plate in your hand. Place the glass plate on a flat surface and then apply the sample. TASTE TEST PRECAUTIONS: The students will NOT perform the taste test on any samples. Sample M19 has a salty taste. CLEAVAGE TEST PRECAUTIONS: Students will NOT be required to hammer or chisel any specimens at home. Observe the samples for evidence of cleavage. FEEL/TEXTURE TEST PRECAUTIONS: If you have a possible allergic reaction to materials such as talc or sulfur, it is best to wear gloves when handling samples. SMELL TEST PRECAUTIONS: Do NOT place you face directly into specimen bags. Gently open the bag and using your hand, make a wafting motion to bring the air/odor towards you. GENERAL PRECAUTIONS: Wash your hands after handling mineral samples. Some samples contain talc and sulfur. 2 MINERAL PROPERTIES: When identifying a mineral, one must conduct tests on a sample. These tests are based on the both the chemical and physical properties minerals have. Both the type and number of atoms present in the material determine such properties. Color- the color of the mineral may give an indication of the types of atoms (chemical composition) that make up the mineral. This happens to be the least reliable test due to contamination! Terms that are commonly used to describe color: white, red, yellow, brown, black, purple, green, blue, grey, or colorless. Transmission of Light describes how a mineral sample reacts to light rays. A mineral can basically be opaque (no light goes through it), translucent (light rays go through the sample, but no distinct image is formed) or transparent (light goes through the sample and an image is observed). Terms used: • translucent (special property) • transparent (special property) • opaque (if not listed the sample is understood to be opaque) The mineral calcite exhibits double refraction. Texture/feel- most minerals will feel rough however certain minerals have smooth or greasy textures. Terms used: greasy (special property), soapy (special property), powdery (special property), slimy (special property), smooth and rough Taste- can identify such minerals like halite, which has a salty taste. Taste is a special property and should only be used as a last resort. DO NOT PERFORM! If you were wet your pinky, apply, or place it on the surface of a clean sample, and place pinky back onto tongue. The instructor will advise you if a sample has a particular taste. 3 Smell- some minerals have unique smells, such as sulfur (S) which smells like rotten eggs. The minerals Galena and Pyrite (Fools Gold), which are sulfide minerals, contain a metal plus sulfur atoms. Smell is a special property. Density (D=M/V) – is the amount of material per unit volume (g/ml). Some minerals, like gold or galena, have a high density (g/ml) and are very “heavy” since they contain “heavy” atoms such as lead. Density is a property highly influenced by chemical composition. Density is calculated by measuring the mass of a sample and dividing it by its volume (the space it occupies). To find the density of a mineral sample you do the following: 1) Measure the dry specimen on a scale and obtain the mass in grams (g). 2) Take a large-mouthed plastic graduated cylinder and add 150 milliliters (ml) water to it. Gently slide the mineral sample into the water and let it sink. Holding the cylinder upright, measure the new water mark. Check graduation scale since some lines represent 5 ml and others the volume between each line may represent 10 ml. Take this number and subtract it from 150 to get the number of milliliters or the volume of the sample. 3) To get the density (D), divide the number of grams (g) by the numbers of ml (ml). A sample problem is done for you below: Sample (unknown) Number: M99 Mass: 200 g Starting water volume: 150 ml Ending water volume: 160 ml Volume of the sample: 160 – 150 = 10 ml Density: 200 g/ 10 ml = 20 g/ml 4 Specific Gravity (s.g.) is the ratio of the density of a mineral compared to the density of an equal volume of water. Since the average density of water is 1g/ml, the specific gravity is usually the same value/number as the density with no units. Ex: The density of gold is approximately 20 g/ml. The density of water is about 1 g/ml. The specific gravity of gold is: s.g. = Dgold/Dwater = 20g/ml / 1g/ml = 20 Since gold has a specific density of 20 we would say that given equal volumes of gold and water, gold is approximately 20 x denser than water. Tenacity- some minerals, like the mica sheets, can be bent without breaking and return to their original shape. This is considered a special property. Malleability- some of the minerals, primarily the metallic minerals, can be shaped, flattened or hammered. Copper is a malleable mineral. This is a special property. Magnetism- some minerals contain large quantities of iron atoms which promote magnetism. Magnetism is a special property. Hardness- is the ability of a mineral to resist scratching. Because of their unique atomic composition and alignment, some minerals will scratch others (Mohs Scale). Talc is the softest mineral (rating = 1) and is scratched by all other known minerals. Diamond is the hardest mineral (rating = 10) and scratches all other known minerals. You can compare the hardness of your sample to various other materials such as glass (5.5), copper (3.5) and even the human fingernail (2.5). 5 Hardness is reported/recorded using the following scales: Mineral does not scratch your finger nail………………… (< 2.5) Hardness less than 2.5 Mineral scratches fingernail but not copper strip………… (2.5 – 3.5) between 2.5 and 3.5 Mineral scratches copper strip but not glass plate………… (3.5 – 5.5) between 3.5 and 5.5 Mineral scratches the glass plate………………………… 5.5) greater than 5.5 (> If the sample and the known material DO NOT SCRATCH each other this means that both items have the same hardness! A sample of the mineral quartz scratches a glass plate. 6 Cleavage/fracture- because of their crystalline structure, some minerals will break and produce smooth lines (cleavage) while others will produce irregular planes (fracture). Regardless of size, samples of the same mineral that exhibits cleavage will always have the same cleavage, thus the same angles. The following terms are used to describe cleavage: 0 directions of cleavage (fracture) 1 direction of cleavage (sheet) 2 directions at 900 (rectangle) 2 directions not at 900 (parallelogram) 3 directions at 900 (cube) 3 directions not at 900 (rhombohedron) 4 directions (octahedron) 7 Streak- because of their internal atomic makeup, some minerals leave distinctlycolored streaks when rubbed against a WHITE porcelain plate. Note the color of the streak if present. If the streak is lighter in color, use the black streak plate. Some samples may not produce a streak at all depending on the sample’s hardness. 8 The mineral graphite, exhibiting metallic luster and a dark streak, is shown above. Luster- minerals may also have metallic (metal-like), glassy or pearly exteriors while other minerals may not have a metallic luster at all (dull, earthy). Terms used: metallic (shines like a metal), non-metallic (does not shine like a metal) and additional terms used to describe non-metallic minerals include: earthy, dull, soil-like, concrete, pearly and glassy. The two varieties of the mineral hematite are shown (metallic and dull) above. 9 Acid test- some minerals, primarily those that are made up of carbonate or CO3 like calcite, will fizz or effervesce when in contact with a few drops of hydrochloric acid. The carbonate has been converted into carbon dioxide (CO2) which causes the bubbles. Goggles and gloves are to be worn when performing the acid (chemical) test. Terms used: Acid negative (-) or acid positive (+) (fizzes = special property) A sample of the mineral calcite is shown above reacting positively to acid. Crystal form or habit- represents the external appearance or shape of a mineral that results from an orderly internal arrangement of atoms under natural, un-restricted conditions. This is NOT the same as cleavage! This property is influenced by crystalline structure. Most samples, such as quartz, have a crystalline structure BUT due to overcrowding and pressure do not exhibit these forms readily. 10 11 CLASSIFICATION OF MINERALS: There are two basic types or classes of the 4000+ minerals: the silicates and non-silicates. 1) SILICATES- THESE MINERALS CONTAIN THE SILICON-OXYGEN (SiO4) TETRAHEDRAL and make up the majority of mineral located in the Earth’s crust. 2) NON-SILICATES – THESE MINERALS DO NOT CONTAIN THE SILICONOXYGEN TETRAHEDRAL AND ARE FURTHER SUBDIVIDED INTO THE FOLLOWING CATEGORIES: • • • • • • NATIVES – Silver (Ag), gold (Au), platinum (Pt), and carbon (C). CARBONATES- these minerals have carbonate (CO3) and will respond (fizz) when in contact with acid. HALIDES- these minerals will have either chlorine (Cl) or Fluorine (F) SULFIDES- these minerals contain Sulfur (S) and an additional type of atom SULFATES- these minerals contain Sulfur (S) and oxygen (O) which form sulfate (SO4) OXIDES- these minerals contain oxygen (O). COMMON MINERAL USES: 1) SILVER (Ag) – photography, jewelry, dentistry 2) SULFUR (S)- drug and chemical manufacturing 3) COPPER (Cu)- electrical wiring, fixtures, jewelry 4) GRAPHITE ( C )- pencil lead and lubricant 5) GYPSUM- plaster 6) TALC- found in ceramics, paint and powder 7) HEMATITE & MAGNETITE- mined for iron 8) GOLD- dentistry, jewelry 9) GALENA – mined for lead 10) KAOLINITE- used in ceramics and china 11) ASBESTOS- formerly used as insulator 12) HALITE – food preservative 13) BIOTITE and MUSCOVITE & OLIVINE – rock forming 14) QUARTZ- used in the manufacturing of glass Many of the other minerals resented in the text are generally also considered rockforming minerals. 12 MINERAL IDENTIFICATION KEYThe lab manual goes through the steps that are needed to be completed for each diagnostic test (color, hardness, acid, etc.) that you are performing on all your samples. You will collect and record your data on figure 1.23, page 14. There is a mineral ID key located on pages 16 – 18 in your lab manual (Applications and Investigations). Once you have completed all of your diagnostic tests on your samples try and match up as many of the properties of your samples to the properties of the known minerals (names for the known minerals are in the yellow box in the ID key. The tutor can check your answers for you if you like. You can send him/her an email with your sample number and your proposed name (i. e. M99 = diamond). The information you collect may be needed to answer several questions of the lab report on pages 23 and 24. NOTE: If one or two properties of your unknown samples do not match up with what you think is the known mineral, yet the remaining dozen properties do match, chances are you have correctly identified that mineral. NOTE: Online students should write down the sample names and numbers at the bottom of the SRP. 13 UNKNOWN MINERAL SAMPLES – SUMMER 2021 If you do not have your lab kit, you may use these samples for lab exercise 1. Use your mineral chart to fill in properties (color, luster, etc.) of the following unknown minerals. None of these samples are magnetic. Some special properties may be listed below each specimen to help you. Mineral Sample M1 • • • • • Note the tarnish Can be hammered or shaped Hardness: 2.5 – 5.5 Copper streak. Density about 9 g/ml 14 Minerals Sample M2 • • • • • • • • • This sample would fracture conchoidally. No cleavage. This sample is pink, but it comes in a wide variety of colors. Scratches glass easily. Does not have metallic luster although it looks shiny. Does not bend. Density approximately 3 g/ml. Hardness: greater than 5.5. (scratches glass) Opaque or at times translucent. 15 Mineral Sample M3 • • • • • • • This sample is transparent. Does not bend. Is not brittle. Reacts positively to hydrochloric acid. May be colorless, white, or pale yellow. Hardness: 2.5 – 5.5. Smooth texture. 3 directions of cleavage @ 750 16 Mineral Sample M4 • • • • • • • This sample is yellow in color. Rotten egg smell. Fractures. Splinters at times. Does not bend. Opaque. Non-metallic luster. 17 Mineral Sample M5 • • • • • • • • This sample is not transparent. Does not bend. Is not brittle. Could be made into sheets. Can be molded and hammered. Yellow color. May slightly smell like rotten eggs. Metallic luster. Density: about 5 g/ml. Hardness: greater than 5.5. 3 directions of cleavage @ 900 18 Mineral Sample M6 • • • • • • • • This sample is transparent except if it very thin. Does bend and can be brittle. Reacts negatively to hydrochloric acid. May be black, brown or both. Look shiny but is not metallic in luster. Hardness: 2.5 – 5.5. Smooth texture. 1 direction of cleavage (basal, sheet) 19 Mineral Sample M7 • • • • • • • • • This sample may be opaque, translucent, or transparent. Does not bend. Is not brittle. Reacts negatively to hydrochloric acid. May be colorless or white. Hardness: 2.5 – 5.5. Salty taste. Smooth texture. Non-metallic luster. 3 directions of cleavage @ 900 20 MINERAL PROPERTIES CHART: Fill in the data chart with the information provided in the unknown mineral sample descriptions. This chart can be used in place of lab manual page 14. You may fill in your sample numbers (from the lab kit samples) and remove the others if you want to use this table. SAMPLE OPTICS COLOR STREAK CLEAVAGE FRACTURE TASTE ODOR TEXTURE HARDNESS # m99 opaque black black no yes no none rough > 5.5 M1 M2 M3 M4 M5 M6 M7 SAMPLE TENACITY- TENACITY- TENACITY- LUSTER MAGNETIC ACID MASS VOLUME DENSITY # ELASTIC BRITTLE MALLEABLE REACTION m99 no no no metallic yes no 52.0 10 ml 5.2 g/ml g M1 M2 M3 M4 M5 M6 M7 21 IDENTIFICATION KEYS/CHARTS: Using the Mineral Data Chart and the ID Keys, identify the name of the unknown samples. Sample M99 is depicted below. 22 23 24 Once your unknown mineral sample is identified, you must determine its use. 25 SAMPLE # m99 MINERAL NAME magnetite MINERAL USE mined for iron M1 M2 M3 M4 M5 M6 M7 26 LAB 1 (THE STUDY OF MINERALS) SUPPLEMENTAL LAB PACKET REPORT PAGES You may submit this in place of the lab manual lab report (pages 23 and 24) if you do not have your lab kit. Name: ________________________________ Section: _____________ Date: _______ 1) Check off the box of the mineral samples exhibiting metallic luster. 2) Complete the following table: SAMPLE MATERIAL IS THIS A MINERAL? YES OR NO. RATIONALE RAINWATER SYNTHETIC RUBIES NATURAL GAS GOLD WOOD PLASTIC HALITE QUARTZ ICE WOOL 27 3) With the data you gathered along with using the identification keys/charts, list the unknown mineral samples name and economic use: SAMPLE # M99 MINERAL NAME magnetite MINERAL USE mined for iron M1 M2 M3 M4 M5 M6 M7 4) Which sample below, A or B, is harder? _______ 5) Describe the cleavage pattern (if applicable) of each mineral sample listed below. Fill in the table. MINERAL SULFUR TALC GYPSUM FLOURITE CALCITE BIOTITE HALITE QUARTZ POTASSIUM FELDSPAR KAOLINITE CLEAVAGE PATTERN OR FRACTURE 28 6) List a special property associated with each mineral. Fill in the table. MINERAL GRAPHITE SPHALERITE MAGNETITE FLOURITE CALCITE MUSCOVITE HALITE GALENA POTASSIUM FELDSPAR KAOLINITE SPECIAL PROPERTY 7) A mineral sample scratches your fingernail but not a glass plate. How would you describe the mineral’s hardness? _______________________________________________________________ 8) Using the mineral identification charts, name the mineral sample pictured below. _____________________________________________________ 9) List the two most common rock-forming silicate mineral groups. ______________________________________________________________ 10) What is the best term to use to describe the tenacity of muscovite? ______________________________________________________________ 29 Atlantic Cape Community College Earth Science- ESCI100 Minerals Background: Mineral – a naturally occurring, inorganic solid that has unique chemical and physical properties. Minerals are the backbone of rocks. Rocks comprise the very solid Earth we stand on. Minerals are also obtained for use in many commercial, industrial, and medical products that we use. Much of this was discussed in the Matter and Minerals chapter of the textbook. Materials: Online students will have three unknown mineral samples labeled M#. The three unknown samples are representative of a metallic mineral, a dark non-metallic mineral, and a light non-metallic mineral. In addition, the kit should also include black and white porcelain streak plates, a small magnet, a glass plate, a goniometer, and a magnifying glass. If the magnifying glass is not in the kit, you can use the stereoscope. Students should have access to some white vinegar (to substitute for hydrochloric acid), a penny (copper strip) and a paper clip. All lab kit materials should be kept away from children. Suggestions: Students will perform diagnostic tests on mineral samples, compare your results to known properties listed on the Mineral ID Key and then make an educated guess as to the name of your mineral specimens. There will be different minerals assigned. Part of your grade is based on the correct identification of unknowns. You must post your findings (EX: M99 = gold) in the Minerals lab discussion board. 1 Mineral lab precautions: HANDLING: If you have a possible allergic reaction to materials such as talc or sulfur, it is best to wear gloves when handling samples. ACID TEST PRECAUTIONS: Use caution when handling the vinegar (acetic acid). Use only a few drops. Goggles and gloves are worn when using acetic acid (vinegar). Perform the acid test in a well-ventilated area. If you have mineral sample M16, perform the acid test on it. All others will be considered acid negative will be considered acid negative (-) and are not carbonates. HARDNESS TEST PRECAUTIONS: Use caution when handling glass plates. Do not try and rub a mineral sample with the glass plate in your hand. Place the glass plate on a flat surface and then apply the sample. TASTE TEST PRECAUTIONS: The students will NOT perform the taste test on any samples. Sample M19 has a salty taste. CLEAVAGE TEST PRECAUTIONS: Students will NOT be required to hammer or chisel any specimens at home. Observe the samples for evidence of cleavage. FEEL/TEXTURE TEST PRECAUTIONS: If you have a possible allergic reaction to materials such as talc or sulfur, it is best to wear gloves when handling samples. SMELL TEST PRECAUTIONS: Do NOT place you face directly into specimen bags. Gently open the bag and using your hand, make a wafting motion to bring the air/odor towards you. GENERAL PRECAUTIONS: Wash your hands after handling mineral samples. Some samples contain talc and sulfur. 2 MINERAL PROPERTIES: When identifying a mineral, one must conduct tests on a sample. These tests are based on the both the chemical and physical properties minerals have. Both the type and number of atoms present in the material determine such properties. Color- the color of the mineral may give an indication of the types of atoms (chemical composition) that make up the mineral. This happens to be the least reliable test due to contamination! Terms that are commonly used to describe color: white, red, yellow, brown, black, purple, green, blue, grey, or colorless. Transmission of Light describes how a mineral sample reacts to light rays. A mineral can basically be opaque (no light goes through it), translucent (light rays go through the sample, but no distinct image is formed) or transparent (light goes through the sample and an image is observed). Terms used: • translucent (special property) • transparent (special property) • opaque (if not listed the sample is understood to be opaque) The mineral calcite exhibits double refraction. Texture/feel- most minerals will feel rough however certain minerals have smooth or greasy textures. Terms used: greasy (special property), soapy (special property), powdery (special property), slimy (special property), smooth and rough Taste- can identify such minerals like halite, which has a salty taste. Taste is a special property and should only be used as a last resort. DO NOT PERFORM! If you were wet your pinky, apply, or place it on the surface of a clean sample, and place pinky back onto tongue. The instructor will advise you if a sample has a particular taste. 3 Smell- some minerals have unique smells, such as sulfur (S) which smells like rotten eggs. The minerals Galena and Pyrite (Fools Gold), which are sulfide minerals, contain a metal plus sulfur atoms. Smell is a special property. Density (D=M/V) – is the amount of material per unit volume (g/ml). Some minerals, like gold or galena, have a high density (g/ml) and are very “heavy” since they contain “heavy” atoms such as lead. Density is a property highly influenced by chemical composition. Density is calculated by measuring the mass of a sample and dividing it by its volume (the space it occupies). To find the density of a mineral sample you do the following: 1) Measure the dry specimen on a scale and obtain the mass in grams (g). 2) Take a large-mouthed plastic graduated cylinder and add 150 milliliters (ml) water to it. Gently slide the mineral sample into the water and let it sink. Holding the cylinder upright, measure the new water mark. Check graduation scale since some lines represent 5 ml and others the volume between each line may represent 10 ml. Take this number and subtract it from 150 to get the number of milliliters or the volume of the sample. 3) To get the density (D), divide the number of grams (g) by the numbers of ml (ml). A sample problem is done for you below: Sample (unknown) Number: M99 Mass: 200 g Starting water volume: 150 ml Ending water volume: 160 ml Volume of the sample: 160 – 150 = 10 ml Density: 200 g/ 10 ml = 20 g/ml 4 Specific Gravity (s.g.) is the ratio of the density of a mineral compared to the density of an equal volume of water. Since the average density of water is 1g/ml, the specific gravity is usually the same value/number as the density with no units. Ex: The density of gold is approximately 20 g/ml. The density of water is about 1 g/ml. The specific gravity of gold is: s.g. = Dgold/Dwater = 20g/ml / 1g/ml = 20 Since gold has a specific density of 20 we would say that given equal volumes of gold and water, gold is approximately 20 x denser than water. Tenacity- some minerals, like the mica sheets, can be bent without breaking and return to their original shape. This is considered a special property. Malleability- some of the minerals, primarily the metallic minerals, can be shaped, flattened or hammered. Copper is a malleable mineral. This is a special property. Magnetism- some minerals contain large quantities of iron atoms which promote magnetism. Magnetism is a special property. Hardness- is the ability of a mineral to resist scratching. Because of their unique atomic composition and alignment, some minerals will scratch others (Mohs Scale). Talc is the softest mineral (rating = 1) and is scratched by all other known minerals. Diamond is the hardest mineral (rating = 10) and scratches all other known minerals. You can compare the hardness of your sample to various other materials such as glass (5.5), copper (3.5) and even the human fingernail (2.5). 5 Hardness is reported/recorded using the following scales: Mineral does not scratch your finger nail………………… (< 2.5) Hardness less than 2.5 Mineral scratches fingernail but not copper strip………… (2.5 – 3.5) between 2.5 and 3.5 Mineral scratches copper strip but not glass plate………… (3.5 – 5.5) between 3.5 and 5.5 Mineral scratches the glass plate………………………… 5.5) greater than 5.5 (> If the sample and the known material DO NOT SCRATCH each other this means that both items have the same hardness! A sample of the mineral quartz scratches a glass plate. 6 Cleavage/fracture- because of their crystalline structure, some minerals will break and produce smooth lines (cleavage) while others will produce irregular planes (fracture). Regardless of size, samples of the same mineral that exhibits cleavage will always have the same cleavage, thus the same angles. The following terms are used to describe cleavage: 0 directions of cleavage (fracture) 1 direction of cleavage (sheet) 2 directions at 900 (rectangle) 2 directions not at 900 (parallelogram) 3 directions at 900 (cube) 3 directions not at 900 (rhombohedron) 4 directions (octahedron) 7 Streak- because of their internal atomic makeup, some minerals leave distinctlycolored streaks when rubbed against a WHITE porcelain plate. Note the color of the streak if present. If the streak is lighter in color, use the black streak plate. Some samples may not produce a streak at all depending on the sample’s hardness. 8 The mineral graphite, exhibiting metallic luster and a dark streak, is shown above. Luster- minerals may also have metallic (metal-like), glassy or pearly exteriors while other minerals may not have a metallic luster at all (dull, earthy). Terms used: metallic (shines like a metal), non-metallic (does not shine like a metal) and additional terms used to describe non-metallic minerals include: earthy, dull, soil-like, concrete, pearly and glassy. The two varieties of the mineral hematite are shown (metallic and dull) above. 9 Acid test- some minerals, primarily those that are made up of carbonate or CO3 like calcite, will fizz or effervesce when in contact with a few drops of hydrochloric acid. The carbonate has been converted into carbon dioxide (CO2) which causes the bubbles. Goggles and gloves are to be worn when performing the acid (chemical) test. Terms used: Acid negative (-) or acid positive (+) (fizzes = special property) A sample of the mineral calcite is shown above reacting positively to acid. Crystal form or habit- represents the external appearance or shape of a mineral that results from an orderly internal arrangement of atoms under natural, un-restricted conditions. This is NOT the same as cleavage! This property is influenced by crystalline structure. Most samples, such as quartz, have a crystalline structure BUT due to overcrowding and pressure do not exhibit these forms readily. 10 11 CLASSIFICATION OF MINERALS: There are two basic types or classes of the 4000+ minerals: the silicates and non-silicates. 1) SILICATES- THESE MINERALS CONTAIN THE SILICON-OXYGEN (SiO4) TETRAHEDRAL and make up the majority of mineral located in the Earth’s crust. 2) NON-SILICATES – THESE MINERALS DO NOT CONTAIN THE SILICONOXYGEN TETRAHEDRAL AND ARE FURTHER SUBDIVIDED INTO THE FOLLOWING CATEGORIES: • • • • • • NATIVES – Silver (Ag), gold (Au), platinum (Pt), and carbon (C). CARBONATES- these minerals have carbonate (CO3) and will respond (fizz) when in contact with acid. HALIDES- these minerals will have either chlorine (Cl) or Fluorine (F) SULFIDES- these minerals contain Sulfur (S) and an additional type of atom SULFATES- these minerals contain Sulfur (S) and oxygen (O) which form sulfate (SO4) OXIDES- these minerals contain oxygen (O). COMMON MINERAL USES: 1) SILVER (Ag) – photography, jewelry, dentistry 2) SULFUR (S)- drug and chemical manufacturing 3) COPPER (Cu)- electrical wiring, fixtures, jewelry 4) GRAPHITE ( C )- pencil lead and lubricant 5) GYPSUM- plaster 6) TALC- found in ceramics, paint and powder 7) HEMATITE & MAGNETITE- mined for iron 8) GOLD- dentistry, jewelry 9) GALENA – mined for lead 10) KAOLINITE- used in ceramics and china 11) ASBESTOS- formerly used as insulator 12) HALITE – food preservative 13) BIOTITE and MUSCOVITE & OLIVINE – rock forming 14) QUARTZ- used in the manufacturing of glass Many of the other minerals resented in the text are generally also considered rockforming minerals. 12 MINERAL IDENTIFICATION KEYThe lab manual goes through the steps that are needed to be completed for each diagnostic test (color, hardness, acid, etc.) that you are performing on all your samples. You will collect and record your data on figure 1.23, page 14. There is a mineral ID key located on pages 16 – 18 in your lab manual (Applications and Investigations). Once you have completed all of your diagnostic tests on your samples try and match up as many of the properties of your samples to the properties of the known minerals (names for the known minerals are in the yellow box in the ID key. The tutor can check your answers for you if you like. You can send him/her an email with your sample number and your proposed name (i. e. M99 = diamond). The information you collect may be needed to answer several questions of the lab report on pages 23 and 24. NOTE: If one or two properties of your unknown samples do not match up with what you think is the known mineral, yet the remaining dozen properties do match, chances are you have correctly identified that mineral. NOTE: Online students should write down the sample names and numbers at the bottom of the SRP. 13 UNKNOWN MINERAL SAMPLES – SUMMER 2021 If you do not have your lab kit, you may use these samples for lab exercise 1. Use your mineral chart to fill in properties (color, luster, etc.) of the following unknown minerals. None of these samples are magnetic. Some special properties may be listed below each specimen to help you. Mineral Sample M1 • • • • • Note the tarnish Can be hammered or shaped Hardness: 2.5 – 5.5 Copper streak. Density about 9 g/ml 14 Minerals Sample M2 • • • • • • • • • This sample would fracture conchoidally. No cleavage. This sample is pink, but it comes in a wide variety of colors. Scratches glass easily. Does not have metallic luster although it looks shiny. Does not bend. Density approximately 3 g/ml. Hardness: greater than 5.5. (scratches glass) Opaque or at times translucent. 15 Mineral Sample M3 • • • • • • • This sample is transparent. Does not bend. Is not brittle. Reacts positively to hydrochloric acid. May be colorless, white, or pale yellow. Hardness: 2.5 – 5.5. Smooth texture. 3 directions of cleavage @ 750 16 Mineral Sample M4 • • • • • • • This sample is yellow in color. Rotten egg smell. Fractures. Splinters at times. Does not bend. Opaque. Non-metallic luster. 17 Mineral Sample M5 • • • • • • • • This sample is not transparent. Does not bend. Is not brittle. Could be made into sheets. Can be molded and hammered. Yellow color. May slightly smell like rotten eggs. Metallic luster. Density: about 5 g/ml. Hardness: greater than 5.5. 3 directions of cleavage @ 900 18 Mineral Sample M6 • • • • • • • • This sample is transparent except if it very thin. Does bend and can be brittle. Reacts negatively to hydrochloric acid. May be black, brown or both. Look shiny but is not metallic in luster. Hardness: 2.5 – 5.5. Smooth texture. 1 direction of cleavage (basal, sheet) 19 Mineral Sample M7 • • • • • • • • • This sample may be opaque, translucent, or transparent. Does not bend. Is not brittle. Reacts negatively to hydrochloric acid. May be colorless or white. Hardness: 2.5 – 5.5. Salty taste. Smooth texture. Non-metallic luster. 3 directions of cleavage @ 900 20 MINERAL PROPERTIES CHART: Fill in the data chart with the information provided in the unknown mineral sample descriptions. This chart can be used in place of lab manual page 14. You may fill in your sample numbers (from the lab kit samples) and remove the others if you want to use this table. SAMPLE OPTICS COLOR STREAK CLEAVAGE FRACTURE TASTE ODOR TEXTURE HARDNESS # m99 opaque black black no yes no none rough > 5.5 M1 M2 M3 M4 M5 M6 M7 SAMPLE TENACITY- TENACITY- TENACITY- LUSTER MAGNETIC ACID MASS VOLUME DENSITY # ELASTIC BRITTLE MALLEABLE REACTION m99 no no no metallic yes no 52.0 10 ml 5.2 g/ml g M1 M2 M3 M4 M5 M6 M7 21 IDENTIFICATION KEYS/CHARTS: Using the Mineral Data Chart and the ID Keys, identify the name of the unknown samples. Sample M99 is depicted below. 22 23 24 Once your unknown mineral sample is identified, you must determine its use. 25 SAMPLE # m99 MINERAL NAME magnetite MINERAL USE mined for iron M1 M2 M3 M4 M5 M6 M7 26 LAB 1 (THE STUDY OF MINERALS) SUPPLEMENTAL LAB PACKET REPORT PAGES You may submit this in place of the lab manual lab report (pages 23 and 24) if you do not have your lab kit. Name: ________________________________ Section: _____________ Date: _______ 1) Check off the box of the mineral samples exhibiting metallic luster. 2) Complete the following table: SAMPLE MATERIAL IS THIS A MINERAL? YES OR NO. RATIONALE RAINWATER SYNTHETIC RUBIES NATURAL GAS GOLD WOOD PLASTIC HALITE QUARTZ ICE WOOL 27 3) With the data you gathered along with using the identification keys/charts, list the unknown mineral samples name and economic use: SAMPLE # M99 MINERAL NAME magnetite MINERAL USE mined for iron M1 M2 M3 M4 M5 M6 M7 4) Which sample below, A or B, is harder? _______ 5) Describe the cleavage pattern (if applicable) of each mineral sample listed below. Fill in the table. MINERAL SULFUR TALC GYPSUM FLOURITE CALCITE BIOTITE HALITE QUARTZ POTASSIUM FELDSPAR KAOLINITE CLEAVAGE PATTERN OR FRACTURE 28 6) List a special property associated with each mineral. Fill in the table. MINERAL GRAPHITE SPHALERITE MAGNETITE FLOURITE CALCITE MUSCOVITE HALITE GALENA POTASSIUM FELDSPAR KAOLINITE SPECIAL PROPERTY 7) A mineral sample scratches your fingernail but not a glass plate. How would you describe the mineral’s hardness? _______________________________________________________________ 8) Using the mineral identification charts, name the mineral sample pictured below. _____________________________________________________ 9) List the two most common rock-forming silicate mineral groups. ______________________________________________________________ 10) What is the best term to use to describe the tenacity of muscovite? ______________________________________________________________

Do you have a similar assignment and would want someone to complete it for you? Click on the ORDER NOW option to get instant services at essayloop.com. We assure you of a well written and plagiarism free papers delivered within your specified deadline.