Name ______Date: / /

Teacher ______per._____

LAB # _____

TITLE: Earth’s Minerals

OBJECTIVE: Of some 4,000 known minerals, only about a dozen called “common rock-forming minerals” make up Earth’s crust. They are identified in the field by a few simple physical tests and observations. This is possible because the physical properties are remarkably constant in a mineral no matter how old it is or where it was formed. In addition to physical tests, there are also some useful diagnostic chemical tests by which minerals can be further identified. In this lab, we will identify some of the most commonly found minerals on the planet, including those you could just find on your way to school.

VOCABULARY: mineral, luster, streak, hardness, cleavage, fracture, organic, inorganic, clastic, composition, and monominerallic

MATERIALS: various minerals, streak plates, penny, rock hammer, steel nail, magnifying lens, glass plate, bottle dropper, dilute hydrochloric acid, and paper towels

PROCEDURE:

  1. Determine the properties for each of the minerals by using the tools for appropriate testing. Record your results on the data table. Use the Mineral Identification Chart below.

2. Use the Properties of Common Minerals Chart and the Mineral Identification Chart and identify each mineral sample by name.

QUESTIONS:

  1. What is the distinction between fracture and cleavage?
  2. Why is color alone not a reliable means of identifying a mineral?
  3. Why is streak a more reliable property than color in mineral identification?
  4. What mineral(s) is usually identified by using the acid test?

CONCLUSION: Explain how minerals are identified, include two additional methods not used in this lab.

ABOVE & BEYOND: Research any four minerals and list their properties and uses, include a picture of it. Do not research any of the minerals used in the lab.

MINERAL IDENTIFICATION CHARTS

FRACTURE

Smooth or rough curved break Fibrous or splintery breakRough surface with sharp edgesRough surface
/
ConchoidalSplinteryHackleyUneven

CLEAVAGE

3 or more good to perfect planes 2 good to perfect planes one good to perfect plane1,2, or more imperfect planesNo planes
/
PerfectParallelBasalPoorNone

LUSTER

Golden, coppery or silvery reflectionA somewhat metallic reflectionAdamantine or vitreous reflectionOily, greasy silky or resinous reflectionEarthy, or non-reflective surface
/
MetallicSubmetallicGlassyWaxyDull

HARDNESS SCALE

Mohs Hardness Scale / Mineral / Simple Test
1 / Talc / Fingernail scratches it easily
2 / Gypsum / Fingernail scratches it
3 / Calcite / Copper penny just scratches it
4 / Fluorite / Steel nail scratches it easily
5 / Apatite / Steel nail scratches it
6 / Feldspar / Steel nail won’tscratch it
It scratches window glass
7* / Quartz / It scratches steel and hard glass
8 / Topaz / Harder than any common mineral
(scratches quartz)
9 / Corundum / It scratches topaz
10 / Diamond / Hardest of all minerals

*Quartz is the hardest common mineral.