Geology 101, Lab Section (20 Points) Your First & Last Name: Geology Lab: The Properties of Minerals & Igneous Rocks Part 1: Minerals This section designed to introduce you to the most common minerals that you will later see in rocks. Use the handout provided and the mineral trays in the geology study room (SC 110) to answer the questions below. Hardness = How strong are minerals? Which of the identified minerals in the tray labeled Minerals/Part I are softer than 2.5? Which of the identified minerals in the tray labeled Minerals/Part I are harder than 5.5? Which minerals SQ-1 SQ-7 (found in the tray labeled Minerals/Part II ) are softer than 2.5? Which minerals SQ-1 SQ-7 (found in the tray labeled Minerals/Part II ) are harder than 5.5? Cleavage = What happens when you break a mineral? Which mineral(s) SQ-1 SQ-7 (found in the tray labeled Minerals/Part II ) display cleavage? The Acid Test (be sure to use safely goggles when conducting this test) Which mineral(s) SQ-1 SQ-7 (found in the tray labeled Minerals/Part II ) react with acid? 1
Fluorescent Rock Display (Front Cabinet Room SC 111) Under white light these minerals are mostly dull white, gray, or black (with some purple). What colors do these minerals glow under ultraviolet light (= black light). Identification of Unknown Minerals Identify the minerals listed below. Note: most rock samples will not have minerals as large as the ones provided here, so take notice of diagnostic characteristics that do not depend on size. Check your answers on this section with me before continuing. mineral # SQ-1 List at least 2 properties other than hardness or cleavage that helped you identify this mineral Mineral Name SQ-2 SQ-3 SQ-4 SQ-5 SQ-6 Mineral ID checked on: by. 2
Part 2: Igneous Rocks Use the Rock ID handout provided and answer the question below by examining the rocks in the trays labeled Part III: Rocks box 1 and Part III, box 2. Texture: 1A) Provide a definition for each texture. (If you re not sure what coarse-grained and fine-grained mean check you notes from class or read the Rock ID handout.) (a.k.a. phaneritic) = (a.k.a. aphanitic) = = How big is a millimeter (mm) anyways? Draw a square with sides 1 mm long in the box below: 1mm = Fill in the tabled below with a check mark under the appropriate texture for each sample listed: Rock Name Course-grained Is this texture volcanic or plutonic (circle one) Andesite Basalt Dacite Gabbro Granite Granodiorite Rhyolite 3
Rocks and Ash: Obsidian (See samples at the front of the room or sample in Box III): Obsidian has a high / low silica (circle one) content, which makes it a mafic / felsic (circle one) rock. Explain why you can t use color to determine if obsidian is mafic or felsic (if you need hint, check your handout or pages 81-82 in your book): Pumice (See samples at the front of the room): The density of pumice is higher/ lower (circle one) than the density of water. What aspect of the texture of pumice explains its unusually density? Based on the color, is pumice more mafic or more felsic (circle one) in composition? Is pumice more likely to form from high viscosity or low viscosity magma? Explain your reasoning. Scoria: (See samples at the front of the room): How does the composition of scoria differ from that of pumice? How does the texture of scoria differ from that of pumice? The density of scoria is higher/ lower (circle one) than the density of water. Ash from Mt. St. Helens (See samples at the front of the room): Examine the color of the sample provided and consider what you know about Mt St. Helens. This ash is / / (circle one) in compositions. Which volcanic rock is it most similar to in color? Describe how the ash samples Ellensburg and Moses Lake differ? Which location was closer to the eruption? Explain your reasoning. 4
Rock Sample Identification Fill in the chart below using samples in boxes Part IV, V-A, & Geology 101: Hoppe (in SC 110) Rock # SQ 15 SQ 17 SQ 24 SQ 25 SQ 27 SQ 30 SQ 35 Rock #1* Composition (circle one) Texture (Circle one) Rock Name Cooling History (circle one) Rock #2* Rock ID checked on: by. 5