Excel spreedsheet
Geology 130 Lab Assignment 1 Mineral Identification You have been provided twelve mineral samples. You will be using these in conjunction with Zumberge’s Laboratory Manual for Physical Geology to complete this lab. First, inside the mineral set should be a square porcelain plate; hold onto this 'streak' plate. In addition, locate a penny, a magnet, a steel nail, a small FLAT piece of glass (or an old drinking glass or yogurt container), and a magnifying glass in your household. We will be using all of these geologic 'tools' to aid in our mineral and rock identification. Most homes will contain these items. If you don't have 1-2 of these items immediately on hand, don't panic, perhaps you can find something in the garage, at the dollar store, or borrow something similar from a friend or neighbor? For example, as far as a magnifying glass goes, I often use my smart phone, take a picture and enlarge. Be creative! Next, familiarize yourself with the Properties of Minerals by reading Pages 2-7 in Zumberge’s Laboratory Manual for Physical Geology or reference the attached Appendix here prior to attempting the following exercises. 1. Using MS Excel – Construct a spreadsheet similar to that displayed on Page 9 of Zumberge’s Laboratory Manual for Physical Geeology; add one additional column entitled ‘Mineral Class’. a. Save the .xls file for use in identification of your mineral samples. b. We will be using the flow charts in Table 1.2 to aid us in identification of our mineral samples (you will also make use of these same flow charts during future Lab Exams). 2. Initial qualitative physical property characteristics – Luster and Color: Compare samples 118 & 119 in the Mineral Set. Both are part of the mica group of minerals with similar chemical composition. Hence, is color a consistent diagnostic property? a. Read the paragraph defining Luster (the quality of light reflecting off the mineral surface) on Page 2 of Zumberge’s Laboratory Manual for Physical Geology. b. Watch the following video on mineral luster: https://youtu.be/hbf1xa9fe_Y c. Record the color and luster of each mineral in the set on your Excel spreadsheet. 3. Quantitative physical property characteristics – Hardness: Mineral hardness is defined as a resistance to scratching. Hardness is defined across a linear scale termed, Moh’s scale of hardness shown in Table 1.1 of Zumberge’s Laboratory Manual for Physical Geology and in the Appendix here. a. We will use the items mentioned above and your fingernail to test each mineral sample for relative hardness. For example, if your fingernail scratches the mineral sample then your fingernail is HARDER than the mineral; similarly, if your mineral scratches your fingernail, then the mineral is HARDER than your fingernail. In addition, you will use a penny, a glass plate, and the white, porcelain streak plate provided to determine hardness. (For those of you that could not locate a flat piece of glass, try the bottom of an old drinking glass turned upside down on your desk.) b. For the correct hardness testing methodology, see this short video here: https://youtu.be/STbhZ6v19Y4. c. Record the relative hardness according to Moh’s scale in your spreadsheet. 4. More physical mineral properties – Cleavage: Cleavage is the tendency of a mineral to break along molecular planes of weakness. Cleavage planes are a direct result of the orientation of https://youtu.be/hbf1xa9fe_Y https://youtu.be/STbhZ6v19Y4 molecular bonds making up the mineral sample. Cleavage may be very obvious or more inconspicuous. a. Review Figure 1.4 in Zumberge’s Laboratory Manual for Physical Geology or the attached Appendix here to familiarize yourself with the number of different cleavage planes (1-6), and their resultant forms. b. Make note of any apparent cleavage planes, including the number of planes and angles, for each mineral sample in your Excel spreadsheet. Notice the rhombohedral cleavage displayed by sample 118 in your mineral kit, or the flat, flakey basal cleavage displayed by this muscovite sample here: 5. Mineral Streak is the color of the minerals powder when rubbing the sample across an unglazed porcelain plate. a. Place the white porcelain plate flat on your table or desk and rub the mineral sample back and forth across the plate as if you were trying to scratch the plate. b. What color is the powdered streak? Record the observation in your spreadsheet. 6. Special Mineral Properties – Specific Gravity, Parting, Fracture, Tenacity, Crystal Form, Odor, Feel, Taste, & Magnetism: Minerals may exhibit a number of additional diagnostic properties that may assist in your deduction of the unknown mineral sample. Familiarize yourself with these special mineral properties as explained in detail on pages 4-7 of Zumberge’s Laboratory Manual for Physical Geology and in the Appendix here. a. Make note of any special mineral properties of each sample in your spreadsheet. i. For example - What does it smell or taste like? Is it magnetic? Is it elastic or flexible? Is it unusually heavy for it’s size? 7. Chemical Group/Mineral Classes – Silicates, Carbonates, Sulfates, Oxides: There are eight major chemical groups that encompass all minerals. Familiarize yourself with these mineral classes in Table 1.4 on page 20 of Zumberge’s Laboratory Manual for Physical Geology and in the Appendix here. The aforementioned 4 most common mineral classes are represented in your set. a. Make note of the mineral class of each sample in your spreadsheet. 8. Use the flow charts on Table 1.2 to reveal the identity of the unknown minerals in the Mineral and Cleavage Sets in your possession. a. Record mineral IDs on your Excel spreadsheet. b. Paste a picture (png or jpeg) of each mineral sample in an Excel column next to your mineral ID. Verify against the mineral catalog displayed in Table 1.3. c. Email this MS Excel spreadsheet to your professor for review and grading: bfreder6@jccc.edu. mailto:bfreder6@jccc.edu APPENDIX PHYSICAL PROPERTIES OF MINERALS Mineral: A naturally-occurring inorganic crystalline solid with definite (although not fixed) chemical composition. Although more than 2,000 different mineral species have been identified, only 25 or 30 are abundant constituents of rocks. The purpose of this exercise is to acquaint you with these common rock-forming minerals. The most diagnostic physical properties of these minerals are listed in the Mineral Identification Index. Crystal Habit If a mineral crystallizes without any impediments to its growth, the mineral may assume a characteristic shape (or crystal habit) that reflects its internal crystal structure. For example, muscovite will often display a book- like tabular habit that results from the arrangement of it silicate tetrahedra in a sheet structure, and halite forms nearly perfect cubes with flat square crystal faces, reflecting the cubic arrangement of its atoms. Other common crystal habits are illustrated on the diagram below. The term anhedral is used to describe minerals without well-formed crystal faces. Luster The way the fresh surface of a mineral reflects light is called its luster. Most minerals may be divided by their luster into metallic and nonmetallic groups. The luster of nonmetallic minerals may be further divided using descriptive terms such as pearly or resinous. Varieties of luster and mineral examples are provided below. TYPE DESCRIPTION MINERAL EXAMPLES Metallic Galena, pyrite NONMETALLIC: Vitreous Shiny like glass Quartz Pearly Milky reflectance like pearl Talc Silky Fibrous appearance Asbestos Resinous Appearance of resin Sphalerite, sulfur Dull Earthy appearance Kaolinite, limonite Greasy Oily appearance Color Color is the most obvious physical characteristic of any mineral specimen. For some mineral species, such as pyrite or galena, it provides a useful clue for identification. Unfortunately, the color of most minerals is highly variable. Although color should always be considered in the course of mineral description, it should never be used as a principle identifying characteristic. Streak The color of a powdered portion of a mineral is known as its streak. Generally, the streak color is different from the color observed in hand sample, and it can be much more diagnostic for identification purposes. Mineral powder may be easily obtained by rubbing a corner of the specimen against a white porcelain surface (or streak plate). Unfortunately, because many light-colored minerals have white or pastel streaks, a streak test is not particularly useful in identifying nonmetallic minerals. Also, minerals which are harder than a streak plate will not be powdered during a streak test. Hardness Hardness is the ability of a mineral to resist abrasion. A mineral’s hardness may be measured by determining how easily it scratches or is scratched by a material of known hardness. The most common standard is the Mohs’ scale of hardness. The scale consists of 10 minerals of different hardness, each assigned a number from 1 to 10. Ten is the hardest and most difficult to scratch. Other materials such as a fingernail, penny, glass, or knife blade may be used to test the unknown mineral’s hardness. Remember that each mineral on the Mohs’ scale has an assigned number and the scale is relative. For example, although fluorite is number 4 on the scale, it is not twice as hard as gypsum (number 2 on the scale), nor is it half as hard as topaz (number 8 on the scale). Also, two minerals with the same hardness will scratch each other. MOHS’ MINERAL HARDNESS SCALE: MATERIAL HARDNESS MOHS’ NUMBER MINERAL 1 Talc Fingernail 2.5 2 Gypsum Penny 3.5 3 Calcite 4 Fluorite Glass Plate 5.5 5 Apatite Knife Blade 6 6 Orthoclase