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:
Minerals at a glance:
- Properties: In short from the above definition we can summarized the main properties of minerals are as follows.
- Definite chemical composition & Structure,
- Natural body without organic particles.
- Ex. Mica, Tale, Quartz,
Properties of Minerals at a glance in a table:
|Basic Identification characteristics||Bauxite||Calcite||Chalcopyrite||Feldspar||Feldspar||Galena||Gypsum||Hematite|
|1. Colour.||White greyish to ocher yellow||White or colorless||Golden yellow||a) Albite / Plagioclase White/Grey||b)Orthoclase Reddish White / Pink||Lead grey||White / Grey||Reddish-brown (outer surface). Black inner surface|
|2. Lustre.||Dull & earthy||vitreous to sub-vitreous||Metallic||sub pearly||sub pearly||Metallic||sub-pearly||Metallic|
|3. Specific gravity||Low||Low||Medium||high to medium||high to medium||Low||low||high|
|4. Hardness||Variable||3||3.5 – 4.0||> 5||> 5||High (7.4 to 7.6.)||<2.5||5.5 to 6.5|
|5. Cleavage||Absent||3 sets Perfect: Rhombohedral||Indistinct||2 sets perfect||2 sets perfect||3 sets Perfect: Cubic||1 set is perfect. 2 other sets are indistinct.||Absent: Parting present|
|6. Streak||White yellow or pale brown||White||Shining greenish black||White||White||Lead gray||White||Cherry red|
|7. Special characteristics||Pisolitic and oolitic||Effervesces briskly with cold & dilute HCl||N/A||N/A||N/A||Sometimes marks on paper||crystalline mineral||Slightly Magnetic|
|Basic identifying characteristics||Magnetite||Mica||Mica||Quartz||Talc||Tourmaline|
|1. Colour.||Iron Black||a)Muscovite white, silver,||b)Biotite Black||White/Greyish white||White/Whitish Grey / Grey,||commonly black|
|2. Lustre.||Metallic||pearly luster||pearly luster||vitreous||silky luster||Vitreous, sometimes resinous|
|3. Specific gravity||very high||very low||very low||Low||low||Medium|
|4. Hardness||5.5 to 6.5||<2.5||<2.5||> 6 (7)||< 2.5||7-7.5|
|5. Cleavage||Absent: Parting present||1 set perfect||1 set perfect||Absent||1 set perfect||Indistinct|
|7. Special characteristics||Strongly Magnetic||transparent and translucent mineral||transparent and translucent mineral||crystalline mineral||soapy feeling||Color range from colorless to brown, red, orange, yellow, green, blue, violet, pink, or hues|
5. Picture of Minerals:
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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.