Mineral Identification Testing Lesson Plan Set up: Print Mineral Identification - Introduction to Mineral Tests Chart for students to record observations. Set up four mineral testing stations as follows: Station #1 Streak Test - graphite, hematite, satin spar (gypsum) - unglazed porcelain tiles - 3 station cards: black with graphite written on reverse, red with hematite written on reverse, white with satin spar (gypsum) written on reverse (station cards and station labels are included at the end this document) Station #2 Luster Test - feldspar, pyrite, pyrolusite, calcite - 3 station cards: vitreous (glassy) with feldspar, calcite written on reverse, metallic with pyrite written on reverse, dull (earthy) with pyrolusite written on reverse Station #3 Transparency Test - biotite mica, magnetite, muscovite mica, selenite (gypsum) - flashlight - 2 station cards: opaque with biotite mica, magnetite written on reverse, translucent to transparent with muscovite mica, selenite (gypsum) written on reverse Station #4 Hardness Test - talc, fluorite, quartz - penny and glass plate - 3 station cards: scratches glass with quartz (MOHS 7) written on reverse, scratches penny but not glass with fluorite (MOHS 4) written on reverse, scratched by fingernail with talc (MOHS 1) written on reverse Note: This lesson plan uses minerals from the Toysmith Mineral Science Kit. For additional explanations, photos, and other downloadable resources referenced in this document, visit. Sample Script A geologist is someone who studies what the earth is made of and how it was formed. We think of the earth as made up of rocks, but these rocks can be broken down into something smaller called minerals. Minerals are the building blocks of rocks! And they are very important to us because minerals are in the products we use every day. They are in our cars, and in our pencils, and in our refrigerators, and in our jewelry, and in our video game consoles, and even in the food we eat! They are EVERYWHERE! Today, we are pretending to be mineralogists, a special type of geologist who studies the chemistry, crystal structure, and physical (including the five senses) properties of minerals. We will identify some minerals by using our observation skills (our five senses). There are many different tests that geologists perform on rocks and minerals to determine what they are. We are going to learn a few of the special tests that mineralogists use to determine what type of mineral they have found. Now that we are geologists/mineralogists, suppose we are hiking and come across a mineral we are not familiar with. How will we figure out what it is? Will we taste it? Will we smell it?
Color and Streak (Test #1) The first thing we will notice is a mineral s apparent color. Although some minerals can be easily identified by color, usually color by itself is not enough to identify a mineral. In fact, sometimes apparent color makes us think a mineral is one thing when it is actually something else. Impurities can cause the color of the mineral to differ from its basic make-up. To find out the color of the mineral in its pure form, we need something else. That something else is called its streak. When a mineral is rubbed firmly across an unglazed porcelain tile, it will leave behind a powder. This is called the streak and remains the same, no matter if the mineral has impurities or not. So let s try the streak test. [Refer to Mineral ID - Introduction to Mineral Tests Chart] Another test we can do with our sense of sight is the luster test, so let s hike over to that station. [Move to Luster station.] Luster (Test #2) Luster is the way a mineral reflects light. The two major groups of luster are metallic and nonmetallic. There are several types of non-metallic luster, including (but not limited to) vitreous or glassy, dull or earthy, pearly, waxy, greasy, and silky. Now, let s try the luster test. [Refer to Mineral ID - Introduction to Mineral Tests Chart] Crystal Form/Habit and Cleavage/Fracture Before we hike to the next station, let s talk about some other visible characteristics of a mineral. Crystal Form/Habit: Minerals grow in specific shapes and usually crystallize in one of six crystal systems. They may crystallize as cubes or in prisms or pyramids. Other ways to describe a mineral s structure include descriptive words such as tabular or needle-like. Cleavage/Fracture: Another characteristic is the way the mineral breaks. If a mineral breaks along a flat surface, it is called cleavage. If it breaks in an uneven or disorganized way (like glass), it is called fracture. Usually you can look at a mineral and tell if it has broken along smooth, flat surfaces or uneven surfaces. The way a mineral breaks and the way its crystals form are two of the most helpful properties to identify minerals. Show students a mineral with special structure (such as pyrite, which has cubic crystal habit) or with visible cleavage (such as biotite mica with 1 cleavage plane (flat sheets) or calcite with 3 cleavage planes (like a rhombic prism)). [Move to Transparency station.] Transparency (Test #3) Transparency is the ability for light to pass through a mineral. Minerals will be either opaque, translucent, or transparent. Opaque: Allows no light to pass through (like a wall) Translucent: Allows some light to pass through, but not enough for object to be seen on other side (like a foggy window)
Transparent: Allows light to pass through so that object may be seen on other side (like a window) [Refer to Mineral ID - Introduction to Mineral Tests Chart] Thankfully we brought a flashlight with us on this hike. Let s place each mineral in front of the flashlight beam to see if we can see through it like a window. [When you test Mica, you can note its cleavage.] [Move to Hardness station.] Hardness (Test #4) The final test we will be doing today is hardness. The hardness of a mineral tells us how well that mineral resists scratching by another substance. We use the MOHS scale, developed in 1812 by a scientist named Friedrich Mohs, to compare minerals to each other. Because we did not bring our MOHS kit with us on this hike, we are going to use some common everyday items to help us determine the hardness of these minerals. 1. Attempt to scratch glass with each mineral. Organize the minerals as hard (scratched the glass) or soft (did not scratch the glass). 2. Attempt to scratch a penny with the soft minerals to determine which are medium hardness. Re-categorize the groups into soft (did not scratch penny) and medium (scratched penny). 3. Attempt to scratch the mineral with your fingernail. These minerals are the softest. On the MOHS hardness scale: Fingernail = 2.5 Penny = 3.5 Glass Plate = 5.5 Visit this link for a MOHS Hardness Scale Chart. [Refer to Mineral ID - Introduction to Mineral Tests Chart] Other tests These are just a few of the tests we can perform on minerals. We can do other things like measure its density or perform chemical tests or test a mineral s magnetism. The main thing to remember from our hike is that when God created the world, he created it with minerals that we use every day, and we can identify these minerals by using our five senses along with some basic tools we normally have available to us. Discussion Questions: Which test did you like the most? Why? What were some of your favorite minerals? Why? Can you create your own test kit to use on rocks and minerals that you find around your home? What would you include in your test kit?
black red white vitreous (glassy) metallic dull (earthy)
hematite graphite feldspar calcite satin spar (gypsum) pyrolusite pyrite
opaque translucent to transparent scratches glass scratches penny but not glass scratched by fingernail
muscovite mica selenite (gypsum) biotite mica magnetite fluorite quartz talc
Station #1 Streak Test
Station #2 Luster Test
Station #3 Transparency Test
Station #4 Hardness Test