The color of a mineral’s streak is not always the same as the color of the mineral sample, as shown in Figure 4. Unlike the surface of a mineral sample, the streak is not affected by weathering. For this reason, streak is more reliable than color as an indicator of a mineral’s identity .
Why is streak useful in identifying minerals?
Streak is the color of a mineral’s powder. Streak is a more reliable property than color because streak does not vary . Minerals that are the same color may have a different colored streak. ... To check streak, scrape the mineral across an unglazed porcelain plate (Figure below).
Is streak is a reliable identifier of a mineral?
Streak is the color of a mineral’s powder . Streak is a more reliable property than color because streak does not vary. Minerals that are the same color may have a different colored streak. ... To check streak, scrape the mineral across an unglazed porcelain plate (Figure below).
Which is more reliable in identifying a mineral?
Streak is more reliable than color to identify minerals. The color of a mineral may vary. Streak does not vary. Also, different minerals may be the same color, but they may have a different color streak.
Why is streak more useful?
Streak is particularly important as a diagnostic for opaque and colored materials . It is less useful for silicate minerals, most of which have a white streak or are too hard to powder easily. The apparent color of a mineral can vary widely because of trace impurities or a disturbed macroscopic crystal structure.
What is the difference between a mineral’s streak and color Why is streak more reliable for rock identification?
Streak is the color of a mineral’s powder. Streak is a more reliable property than color because streak does not vary . Minerals that are the same color may have a different colored streak. Many minerals, such as the quartz in the Figure 3, do not have streak.
Which property is most useful in mineral identification?
Hardness . The ability to resist being scratched—or hardness —is one of the most useful properties for identifying minerals. Hardness is determined by the ability of one mineral to scratch another.
Which is more reliable streak or color?
The color of a mineral in powdered form is called the mineral’s streak. ... Unlike the surface of a mineral sample, the streak is not affected by weathering. For this reason, streak is more reliable than color as an indicator of a mineral’s identity.
When would you not use a streak test to identify a mineral?
For minerals that are harder than the streak plate , this test cannot be used, since the mineral will remove tile material. This is rarely a problem, though, since most minerals where this test will be significant are softer than the streak plate (the streak plate has an average hardness of about 61⁄2 on the Mohs scale).
Which mineral are the same in terms of their streak?
| Streak Colors of Common Minerals | Andalusite White or colorless (hardness is about the same as the streak plate). | Gypsum White. | Halite White. | Hematite Red to reddish brown. |
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What is the least reliable way to identify a mineral?
Color is the least reliable property for mineral identification. The same mineral can come in a variety of colors and different minerals can be the same color.
What is the hardest known mineral on Earth?
Diamond is the hardest known mineral, Mohs’ 10.
Which are examples of tests that can be used for mineral identification?
Geologists use the following tests to distinguish minerals and the rocks they make: hardness, color, streak, luster, cleavage and chemical reaction . A scratch test developed by a German mineralogist Fredriech Mohs in 1822 is used to determine mineral hardness.
What mineral is not scratched by a fingernail but is scratched by a copper penny?
| mineral Mohs hardness observations on the minerals | talc 1 very easily scratched by the fingernail; has a greasy feel | gypsum 2 can be scratched by the fingernail | calcite 3 very easily scratched with a knife and just scratched with a copper coin | fluorite 4 very easily scratched with a knife but not as easily as calcite |
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Why is color often an unreliable property for mineral identification?
Explanation: It is common for one mineral to be naturally found in more than one color. ... Using color alone to identify a mineral could lead to an inaccurate conclusion . The hardness of the mineral, luster, cleavage, fracture, how it reacts to an acid, and other traits can be used to identify what the mineral is.
What mineral is pink or white wavy lines right angles to cleavage planes?
The mineral that is pink or white, has wavy lines right angles, and two cleavage planes is Orthoclase . Orthoclase represents an essential mineral of polysilicate, that shapes up an igneous rock.
