Mineral Identification PDF

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Summary

Presented by Sydney Lee...

Description

Mineral Identification

Step by Step Procedures

Exercises

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To Complete today: Activity 3.4, pages 101 – 104 Mineral Analysis, Identification and Uses chalcopyrite, orthoclase/potassium-feldspar, plagioclase, mica(biotite or muscovite), olivine, hornblende, garnet, kaolinite, quartz, calcite, dolomite, hematite, magnetite, galena, pyrite, talc, gypsum.

Determine Mineral Luster

Metallic or Submetallic

Non-metallic

Usually Opaque If in doubt, it is non-metallic In a rock, consider minerals individually Transparent or translucent materials are always non-metallic Non-metallic lusters : Waxy Pearly Vitreous or glassy Satiny or silky Greasy          

Metallic Minerals

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Determine hardness and record Refer hardness to glass plate test Harder than glass? Softer than glass? Determine streak and record Streak plate hardness = 6.5 Minerals harder than 6.5

do not leave a streak 

(Applies to sub-metallics as well)

Metallic Minerals

Determine and record other properties Color of the fresh and tarnished surface Cleavage (number and angles) Magnetism Crystal habit Etc.      

3 cleavages at 90 degrees

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Cleavage surfaces appear in sets. Sets resemble stair steps. Several parallel reflecting surfaces = cleavage Only one reflecting surface = crystal face

Metallic Minerals

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Identification based on recorded properties Use Figure 3.19, page 85 Check your properties against potential mineral Check mineral database , Figure 3.22, pages 88 - 92 for additional properties Match your sample to a specific mineral.

Fig. 3.19, page 85

Fig. 3.22, pages 88 - 92

Non-Metallic Minerals

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Determine hardness and record Refer hardness to glass plate test Harder than glass? Softer than glass? Determine color

Non-Metallic Minerals - Color

Dark-Colored or Light-Colored? Non ferromagnesian minerals are usually light –colored White, yellow, light gray, pink, red, Ferromagnesian minerals are usually dark-colored Black, brown, dark gray, dark green But there are exceptions… Some ferromagnesian minerals are light Some non-ferromagnesian are dark!        

Confusing Dark-Colored and Light- Colored minerals

Colors: * Some minerals appear in both the light and dark varieties and therefore show in multiple tables  

E.g. Garnets, olivine, quartz, plagioclase, orthoclase, micas

Garnets and olivine

Physical Properties of Minerals

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Miscellaneous Properties magnetism some minerals (e.g., magnetite) are magnetic effervescence some minerals (e.g., calcite, dolomite) will effervesce/fizz in weak hydrochloric acid calcite will react readily, dolomite will react only when powdered

Physical Properties of Minerals

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Miscellaneous Properties striations - useful in distinguishing plagioclase from orthoclase plagioclase has striations on ONE of the two cleavage surfaces; orthoclase does not have striations...