Those minerals that are harder than the unglazed porcelain streak plate will scratch it rather than leave a streak.
Minerals that cannot be determined by a streak plate typically include those that are harder than the streak plate itself, such as diamonds and corundum, as they will not leave a streak. Additionally, minerals that are non-metallic and have a very light color or are transparent may not produce a visible streak. Furthermore, minerals that are powdery or have a very fine texture might not yield reliable streak results.
Diamond and quartz are colorless minerals that also have a colorless streak. This means that when these minerals are scratched against a white ceramic plate, they leave behind a streak that is also colorless.
Streak is not used to identify every mineral because some minerals have the same color streak, making it unreliable for differentiation. Additionally, some minerals are too hard to leave a streak, while others may create a variable streak due to impurities. As a result, streak is just one of several properties used to identify minerals.
Topaz (8), corundum (9), and diamond (10).
Gabbro does not have a streak because it is a coarse-grained rock made up of minerals like plagioclase feldspar and pyroxene that are harder than the streak plate. As a result, gabbro does not leave a streak when rubbed on a streak plate.
A streak test is used to determine a minerals streak color. This can help in the identification of minerals.
Two minerals that do not leave a streak on a streak plate are quartz and fluorite. Both minerals have a hardness higher than that of the streak plate, so they will not leave a streak when rubbed against it.
A streak test is not used to identify minerals with a hardness greater than 7 on the Mohs scale, as these minerals can scratch the streak plate. Additionally, streak tests may not be effective for identifying minerals that have a streak color similar to the streak plate itself.
Streak color is determined by scraping the mineral across a a streak plate, (which is made of unglazed porcelain), and then observing the color of the streak, which is left on the plate. Note that some minerals do not leave a streak, as they are too hard. Thus, it is important to learn other identification methods, to use in conjunction with streak color, in order to identify minerals.
Those minerals that are harder than the unglazed porcelain streak plate will scratch it rather than leave a streak.
Very hard minerals like diamonds can leave no streak because their hardness prevents them from being scratched by the streak plate. Since the streak test involves rubbing the mineral against a surface to leave a streak, extremely hard minerals won't leave a streak behind because they are tougher than the testing material.
Minerals that cannot be determined by a streak plate typically include those that are harder than the streak plate itself, such as diamonds and corundum, as they will not leave a streak. Additionally, minerals that are non-metallic and have a very light color or are transparent may not produce a visible streak. Furthermore, minerals that are powdery or have a very fine texture might not yield reliable streak results.
dark streak
The streak test can only identify minerals that have a consistent powder color when scratched on a rough surface. It may not work well for minerals harder than the streak plate or those with a variable powder color due to impurities. Additionally, some minerals lack a distinguishable streak color, making it unreliable for their identification.
Diamond and quartz are colorless minerals that also have a colorless streak. This means that when these minerals are scratched against a white ceramic plate, they leave behind a streak that is also colorless.
to find the minerals streak, what i the mineral rubbed in