Mineral Mystery Lab - Student Handout

GEOL 121 Name________Christian Malloy_____________- 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. 1

Mineral Mystery Lab GEOL 121 Step 1: Search for clues 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? Light or Dark Group 1 characteristic: light Group 2 characteristic: Dark Group 3 characteristic: dark Mineral(s): A,K,E,F,G, C,B Mineral(s): D,H,I,L,J Mineral(s): Transperensy Group 1 characteristic: solid Group 2 characteristic: transparent Group 3 characteristic (optional): Mineral(s): A,K,D,E,F,H,I,J Mineral(s): C,B,G Mineral(s): Shine or no shine Group 1 characteristic: shine Group 2 characteristic: no shine Group 3 characteristic (optional): Mineral(s): C,E,I,J,B Mineral(s): A,K,D,F,G,L,H Mineral(s): 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 2

Mineral Mystery Lab GEOL 121 Mineral A Mineral F harder then 5.5 color, white, pink, any color Streak: white/colorless glassy Conchoidal fracture common (F) white Softer than 5.5 No pattern Mineral B Mineral J Transparent Bright colorless to pale yellow/gold white/colorless glassy, milky Hardness: 2–2.5 Thin, elastic sheets of micas (J) not transparent Dark brownish Mineral C Mineral G Transparent Shiny No reaction to acid light Reacted to acid Not shiny Mineral D Mineral H Magnetic Harder than 5.5 Not magnetic Softer than 5.5 Mineral E Mineral I 4

Mineral Mystery Lab GEOL 121 Harder than 5.5 Looks lighter Softer than 5.5 Looks darker Mineral H Mineral L Softer than 5.5 Not shiny Harder than 5.5 Shiny 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. Q4 . Now put together all of your observations! List 3–5 physical properties for each mineral: Mineral A White and reddish Mineral B Transparent Mineral C Transparent 5

Mineral Mystery Lab GEOL 121 Mineral J Dark Shiny Softer than 5.5 Cleavage: Single perfect cleavage to produce thin flexible sheets or flakes Mineral K A light orange Harder than 5.5 Not shiny Cleavage: One perfect cleavage and one good cleavage, meet at nearly 90 ° Mineral L Shiny Harder than 5.5 Dark Cleavage: Two directions, that meet at nearly right angles (87 ° and 93 ° ) Step 2: Identify the suspects Q1 . What did you learn from Step 1? I learned how to separate the differences from each mineral . 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. 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 ° Step 3: Solve the Mystery! 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. 8

Mineral Mystery Lab GEOL 121 Mineral C = Halite Mineral G = Calcite Mineral K = Potassium feldspar Mineral D = Magnetite Mineral H = Amphibole Mineral L = Pyroxene Step 4: Reflection Q1 : What did you enjoy about this lab? I enjoyed all the testing with rocks and how we saw the different reactions. Q2 : What was difficult about this lab? Finding all the names of the rocks Q3 : What questions do you still have about identifying minerals? My question is what if two rock are stuck together how do you determine what is what . 10