Mineral Lab.

GEOL 121 Name___Sierra Anguiano__________________________- Lab Section__________________ MINERAL MYSTERY LAB Learning Objectives At the end of this lab students will be able to: ● Observe characteristics of minerals. ● Describe differences in physical properties of minerals ● Use physical properties to identify minerals. ● Develop and produce a system for identifying different minerals via a flow chart. Introduction Ultimately, geology is about storytelling; we can think of the entire Earth’s history as a book, the pages in the book are filled with stories that we developed by looking at the rocks that form our planet. Minerals that make up those rocks help us identify the rocks, so we can tell their stories. We also use minerals in our lives every day, often without even noticing. Minerals are in your cell phone, your car, your countertops (well, some of our countertops anyway) and even your walls. So, not only do minerals help us tell Earth’s story but they also help make our modern lives possible. Minerals come in all shapes, colors, and sizes but they share common characteristics that we can use to sort them into groups. In this lab, you take on the role of a mineralogist by testing various physical properties, sorting minerals into categories with similar characteristics, and then creating a flowchart to use to identify minerals. Step 1: Search for clues 1

Mineral Mystery Lab GEOL 121 Observe the grid of minerals in front of you. None of them are currently named - that’s okay! Before we get into labeling, let’s take a close look at each of the minerals. Q1 . What are some physical characteristics that multiple minerals share? What are three different ways that you could divide these minerals into 2–3 groups based on those characteristics? Option 1 Option 2 Option 3 Once you have come up with three different ways to divide these minerals into groups based on their physical characteristics, compare the groups you made with the other pair of students in your small group. What groups are the same? What groups are different? Is there more than one valid way to group the minerals? Q2 . Take a look at the tools next to your mineral grid. Try out some of these tools on your minerals. Some tools are for getting a closer look at the minerals, some are for scratching the minerals, and some are for checking the streak a mineral makes. The HCl bottle is used to check for effervescence (i.e. a fizz reaction). Are there any similarities between how Group 1 characteristic: Dull Group 2 characteristic: Vitreous Group 3 characteristic (optional): Metallic Mineral(s): A,L,G,K Mineral(s): F,C, B Mineral(s): D,J,F,I, Group 1 characteristic: Silky Group 2 characteristic: Resinous Group 3 characteristic (optional): Greasy Mineral(s): K, A, G Mineral(s): I,F,J Mineral(s): C Group 1 characteristic: Pearlescent Group 2 characteristic: Waxy Group 3 characteristic (optional): Submetallic Mineral(s): C, F, B Mineral(s): J Mineral(s): A, L, G, I 2

Mineral Mystery Lab GEOL 121 -Chalky/Dull -Light streak -Below 5.5 -Negative on Acid -Light white/Light pink streaks -Glassy, Vitreous -is harder then 5.5 -Light streak -Negative on Acid test -Whiter and more clear. Mineral B Mineral J -Glassy, Vitreous, Luster -Not magnetic -Below 2.5 hardness -Negative Reaction to acid -Black and opaque -Not magnetic -Below 2.5 Hardness -Negative reaction to acid Mineral C Mineral G -Glassy, Vitreous - Not magnetic - Hardness 3 - Negative reaction to Acid -White/Dull & opaque -Light white streak -Hardness of 3.5-5.5 Mineral D Mineral H -Black slight/Luster -Light streak -Not magnetic -Hardness 4 -Black, Dull, kinda sub metallic -Not magnetic -Dark streak -Hardness less then 3.5 4

Mineral Mystery Lab GEOL 121 Again, reconvene with your small group. For each mineral pair, discuss what difference you think will be the most useful for distinguishing between the two minerals. Come to a consensus for each mineral pair within your small group. Circle or highlight that difference in each of the tables above. Mineral E Mineral I -Gold, Metalic -Hardness of 4.5 -Not magnetic -No acid reaction -Black, Sub-metallic -Not-magnetic -Hardness of 3 -No acid reaction Mineral K Mineral L -Dull, Pink/Red -Hardness of 5 -Light cleavage -Not magnetic. -Hardness 4.2 -Dull, with Black dots Not magnetic 5

Mineral Mystery Lab GEOL 121 Step 2: Identify the suspects Q1 . What did you learn from Step 1? Q2 . Applying your understanding of mineral physical properties, use the following table (which contains the name and physical properties of minerals) to construct a Mineral Identification Flow Chart. Follow the flow chart, answering the questions for each mineral. Place the correct mineral names in the boxes. Mineral J Mineral K Mineral L Quartz SiO 2 Color: colorless, white, pink, any color Streak: white/colorless Luster: glassy Hardness: 7 Conchoidal fracture common Specific Gravity: 2.65 Plagioclase Feldspar NaAlSi 3 O 8 to CaAl 2 Si 2 O 8 in varying proportions Color: white to green-gray Streak: white/colorless Luster: milky to translucent Hardness: 6 Cleavage: good, 2 planes at 90º Striations on cleavage planes Specific Gravity: 2.62–2.75 Amphibole Ca 2 (Mg,Fe(Ca,Na) 2-3 (Mg,Fe +2 ,Fe +3 , Al) 5 Si 6 (Si,Al) 2 O 22 (OH) 2 Color: black , dark green, dark brown, dark gray Streak: white/colorless Luster: vitreous to dull Hardness: 6 Cleavage: Imperfect 2 directions at 56° and 124° / uneven Specific Gravity: 3–3.4 7

Mineral Mystery Lab GEOL 121 Halite NaCl Color: colorless Streak: white/colorless Luster: glassy Hardness: 2.5 Cleavage: perfect, 3 planes @ 90º Salty taste Muscovite (mica) KAl 2 (AlSi 3 O 10 )(F,OH) 2 Color : colorless to pale yellow/ gold Streak: white/colorless Luster: glassy, milky Hardness: 2–2.5 Specific Gravity: 2.8–2.9 Cleavage: perfect in 1 direction; Thin, elastic sheets of micas Galena PbS Color: gray Streak: gray Hardness: 2.5 Cleavage: good, 3 planes @ 90º Specific Gravity: 7.5 (very dense) Sulfur smell on fresh surfaces Pyrite (fool’s gold) FeS 2 Color: brassy yellow Streak: green-black to black Luster: metallic Hardness: 6–6.5 Specific Gravity: 5.02 Magnetite Fe 3 O 4 Color: dark gray to black Streak: black Luster: metallic Hardness: 5.5-6.5 Specific Gravity: 5.2 Cleavage: none Magnetic Biotite K(Mg,Fe) 3 AlSi 3 O 10 (OH) 2 Color: brown to black Streak: white to gray Luster: pearly to submetallic Hardness: 2.5-3 Specific Gravity: 2.7-3.4 Cleavage: Single perfect cleavage to produce thin flexible sheets or flakes. Calcite CaCO 3 Color: colorless, white, yellow Streak: white/colorless Luster: glassy Hardness: 3 Specific Gravity: 2.71 Cleavage: perfect, 3 planes @ 75º Effervesces in dilute HCl acid Pyroxene (NaCa)(Mg,Fe,Al)(Al,Si) 2 O 6 Color: Usually dark green , dark brown or black Streak: white, greenish white or gray Luster: vitreous (glass-like) Hardness: 5-6 Specific Gravity: 3.2-3.5 Cleavage: Two directions, that meet at nearly right angles (87 ° and 93 ° ) Potassium Feldspar KAlSi 3 O 8 Color: typically shades of peach, orange, or red Streak: white Luster: crystals are vitreous (glass-like) to porcelaneous (porcelain-like) Hardness: 6 Specific Gravity: 2.6 Cleavage: One perfect cleavage and one good cleavage, meet at nearly 90 ° 8

Mineral Mystery Lab GEOL 121 Q1. Applying your understanding of mineral physical properties, use flow chart you made in the previous step to identify your 12 unknown mineral specimens. We will identify Mineral A and Mineral B together as a class. Work in pairs and then share your findings with your larger group. Place your answers in the space provided, in the table below. Enter the names of the minerals in the spaces below. Step 4: Reflection Q1 : What did you enjoy about this lab? Q2 : What was difficult about this lab? Q3 : What questions do you still have about identifying minerals? Mineral A = Mineral E = Mineral I = Mineral B = Mineral F = Mineral J = Mineral C = Mineral G = Mineral K = Mineral D = Mineral H = Mineral L = 10