Rocks and Minerals – Identification of minerals

Introduction:

 The mineral is an inorganic homogeneous natural substance usually crystalline with a definite chemical composition. It is not easy to identify the minerals in the necked eye with a hand specimen of the minerals without proper identification of their structure and chemical composition under a microscope. We can only predict its probability with the help of its properties. In this article, we will discuss the processes of the identification of minerals based on hand specimens.

List of minerals to be identified:

List of Minerals

Minerals at a glance:

  • Properties:  In short from the above definition we can summarized the main properties of minerals are as follows.
    • Inorganic,
    • Homogeneous,
    • Definite chemical composition & Structure,
    • Natural body without organic particles.
  •  Ex. Mica, Tale, Quartz,

Properties of Minerals at a glance in a table:

Basic Identification characteristicsBauxiteCalciteChalcopyriteFeldspar Feldspar GalenaGypsumHematite
1. Colour.White greyish to ocher yellowWhite or colorlessGolden yellowa) Albite / Plagioclase White/Greyb)Orthoclase Reddish White / PinkLead greyWhite / GreyReddish-brown (outer surface). Black inner surface
 2. Lustre.Dull & earthyvitreous to sub-vitreousMetallicsub pearlysub pearlyMetallicsub-pearlyMetallic
3. Specific gravity LowLowMediumhigh to mediumhigh to mediumLowlowhigh
4. HardnessVariable33.5 – 4.0> 5> 5High (7.4 to 7.6.)<2.55.5 to 6.5
5. CleavageAbsent3 sets Perfect: RhombohedralIndistinct2 sets perfect2 sets perfect3 sets Perfect:  Cubic1 set is perfect. 2 other sets are indistinct.Absent: Parting present
6. StreakWhite yellow or pale brownWhiteShining greenish blackWhiteWhite Lead grayWhiteCherry red
7. Special characteristicsPisolitic and ooliticEffervesces briskly with cold & dilute HClN/AN/AN/ASometimes marks on papercrystalline mineralSlightly Magnetic
Minerals with the identification characteristics
Basic identifying characteristicsMagnetiteMicaMicaQuartzTalcTourmaline
1. Colour.Iron Blacka)Muscovite white, silver,b)Biotite BlackWhite/Greyish whiteWhite/Whitish Grey / Grey,commonly black
 2. Lustre.Metallicpearly lusterpearly lustervitreoussilky lusterVitreous, sometimes resinous
3. Specific gravity  very highvery lowvery lowLowlowMedium
4. Hardness 5.5 to 6.5<2.5<2.5> 6 (7)< 2.5 7-7.5
5. CleavageAbsent: Parting present1 set perfect1 set perfectAbsent1 set perfectIndistinct
6. Streak BlackUncoloredUncoloredWhiteWhiteWhite
7. Special characteristicsStrongly Magnetictransparent and translucent mineraltransparent and translucent mineralcrystalline mineralsoapy feelingColor range from colorless to brown, red, orange, yellow, green, blue, violet, pink, or hues
Minerals with the identification characteristics

5. Picture of Minerals:

Bauxite and Calcite
Chalcopyrite
Galena and Gypsum
Hematite and Magnetite
Mica and quartz
Talc and Tourmaline

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Video

Here is the video and complete explanation about the identification of the minerals. Click Here

Conclusion:

These are the identification of minerals, from the above properties of the minerals, we can identify the different minerals at a glance in the field. The process of identification of minerals in hand specimen is very much useful for 1st time observation. We need more information about the components of particular minerals by laboratory test.

Download Photos of the Minerals

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