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Rocks and rock minerals
Published in Ivan Gratchev, Rock Mechanics Through Project-Based Learning, 2019
Streak can be helpful to identify a few minerals. A good example is pyrite, which is also known as ‘fool’s gold’. Pyrite looks like gold (that is why people tend to assume that it is gold); however, it has a black streak unlike the gold mineral with a yellow streak.
Minerals
Published in Dexter Perkins, Kevin R. Henke, Adam C. Simon, Lance D. Yarbrough, Earth Materials, 2019
Dexter Perkins, Kevin R. Henke, Adam C. Simon, Lance D. Yarbrough
For mineral identification, streak is much more reliable than mineral color and is easy to determine. The usual method of determining streak is to rub the mineral against a ceramic streak plate as shown in Figure 3.39. For example, quartz comes in many colors, but its streak is always white (clear). The same is true of calcite. Gold and pyrite (fool’s gold) may have similar appearing colors, but their streaks are always different. Pyrite has a dark-colored streak; gold has a yellowish streak.
Minerals and rocks
Published in A.C. McLean, C. D. Gribble, Geology for Civil Engineers, 2017
The colour of a mineral is that seen on its surface by the naked eye. It may depend on the impurities present in light-coloured minerals, and one mineral specimen may even show gradation of colour or different colours. For these reasons, colour is usually a general rather than specific guide to which mineral is present. Iridescence is a play of colours characteristic of certain minerals. The streak is the colour of the powdered mineral. This is most readily seen by scraping the mineral across a plate of unglazed hard porcelain and observing the colour of any mark left. It is a diagnostic property of many ore minerals. For example, the lead ore, galena, has a metallic grey colour but a black streak.
An unconventional approach in investigating wettability contact angle measurement in shale resources
Published in Petroleum Science and Technology, 2022
Salah Almudhhi, Mohammed Alostath, Waleed Al-Bazzaz, Hamid Sharifigaliuk, Ali Qubian
The second step for the unconventional mineralogy characterization is identifying the 18 minerals with their different physical properties (Sewailan and Al-Bazzaz 2019). There are 10 physical properties considered for the unconventional study of global shale rock minerals identification (Table 3). These physical properties are: chemical group, chemical sub-group, mineral name, chemical formula, mineral density, mineral cleavage, mineral tenacity, mineral hardness (Mohs Scale), mineral streak, mineral natural color, and mineral abundance in shale. Other physical properties will not be discussed in this study are mineral: luster, specific gravity, taste, odor, magnetism, and chemical reaction with acids.