Materials Based One Per Lab Group of Four

Exploring Minerals

Materials based one per lab group of four

Testing Supplies 24oz. Ziplock container (to build each kit in) Streak Plate Glass Plate Copper Penny Iron Nail Bottle of dilute hydrochloric acid (8%) 100 ml Graduated Cylinder Balance Water

Minerals should be ordered as testing samples (usually in packs). You should have 2-3 samples per group for comparison.

Minerals Calcite Feldspar Galena Graphite Hematite Muscovite Pyrite Quartz

Use the chart to explore and identify the physical properties of minerals. Students should note that rock and mineral testing requires inexpensive easily transported equipment that can be carried on hikes and camping trips. Step 1 – Identify each mineral and arrange using the mineral identification paper.

Step 2 – Complete the first column of the Mineral Datea Table by listing each mineral.

Step 3 – Observe and record the color or colors of each mineral sample (note this may be different for different samples). Discuss as a class to identify concensus.

Step 4 – Rub each mineral across the streak plate to identify its true color. Tell students that reguardless of a minerals appearance the streak is consistant for each mineral. Record the minerals true color in the streak column.

Step 5 – Use the luster chart to identify the luster of each mineral. Minerals are first categorized as metallic or nonmetallic. If metallic there is no further test, it is simply recorded as metallic. If nonmetallic it is categorized as; brilliant, greasy, pearly, resinous, dull, silky, or vitreous.

Step 6 – Use Moh’s Hardness Scale to determine the hardness of each mineral. Testing a mineral until it is scratched by the tool. The tool that was last used, but didn’t scratch it determines its hardness. The tools in order of testing are; fingernail, copper penny, iron nail, glass plate, porcelain streak plate.

Step 7 – Use the cleavage/fracture key to determine each minerals designation. First categorizing by cleavage or fracture. Then use the ket to determine which type of cleavage or fracture occurred.

Step 8 – Use the balance to find the mass of each mineral sample in grams.

Step 9 – Use the graduated cylinder and water to find the volume of the same mineral sample that you found the mass for. 1ml = 1cm cubed. Record the sample in terms of cm cubed.

Step 10 – Find the density of that mineral sample by dividing (g/cm cubed). Record density in terms of (g/cm cubed) (I can’t type the small 3 for cubed).

Step 11 – Answer questions about each sample. Questions

1. According to the mineral data table what are at least two properties that can identify graphite and galena, assuming the minerals are the same size? ______2. What is the softest mineral tested? ______3. What is the hardest mineral tested? ______4. Define what is meant by streak color? ______5. Which sample had a streak color that was dramatically different than the sight color? ______6. List the minerals tested that have a metallic luster. ______7. Which mineral fizzed when tested with hydrochloric acid? ______8. What does the fizz indicate the presence of in the sample? ______9. Which of the mineral samples had the highest density? ______Name Sight True Luster Hardness Cleavage Mass Volume Density Special Illustration Color Color Or Properties Or Fracture Streak Moh’s Hardness Scale Testing Tools

Object Hardness Fingernail 2.5 Copper Penny 3.5 Steel Nail 5 Glass Plate 5.5 Streak Plate 6.5 Diamond 10

The classic scale for hardness was published in 1822 by Frederick Mohs, an Austrian mineralogist who got the basic concept from scratch tests performed routinely by miners. Since Mohs published the scale, it bears his name rather than that of the unknown genius who thought of it. The scale selects 10 minerals as standards, arranging in order of increasing hardness. These are, as most of you probably know:

1 = Talc 2 = Gypsum 3 = Calcite 4 = Fluorite 5 = Apatite (fluorapatite) 6 = Orthoclase 7 = Quartz 8 = Topaz 9 = Corundum 10 = Diamond Fracture and Cleavage –

Mineral Name ______Type of Fracture or Cleavage ______

Illustration

Degree Number of planes Of Smoothness One Two Three Perfect

Illustration

Poor Mineral Name ______Type of Fracture or Cleavage ______

Illustration