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Why doesn't the mineral topaz leave a streak on a streak plate?
Wiki User
∙ 12y ago
It leaves a scratch instead of a streak because Topaz has a higher number on the Moh's scale compared to the streak plate.
Wiki User
∙ 12y ago
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If a mineral doesn't make a streak is it not a mineral?
Minerals with a hardness greater than around 7 on the Mohs hardness scale will not leave a streak on a standard unglazed porcelain streak plate. They will instead scratch and powder the streak plate.
What is a piece of unglazed porcelain to test a mineral's streak called?
A streak plate
What can you rub a mineral on to leave a clue what the mineral?
A streak plate, or unglazed white porcelain tile, is used to perform streak tests which can help to identify minerals. Rubbing the mineral on the streak plate will finely powder it and reveal the color of the powder, which in some cases is quite different from the color of the mineral. Eg: hematite is black but has a red streak - a good way to tell you have hematite instead of one of the many other shiny black minerals.
How is a minterals streak determinded?
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.
Why can't a streak test be done on a mineral whose hardness is greater than 7?
Because the mineral is harder than the ceramic streak plate.
What happens if you rub the mineral across a streak plate but the mineral does not leave a streak?
The lack of a streak would indicate that the mineral is harder than the streak plate, or the color of the streak is the same as the color of the streak plate.
Will diamond leave a streak on a streak plate?
Diamond will not leave a streak on a porcelain streak plate because diamond is harder than the streak plate. It will leave a scratch on the streak plate for the same reason.
If a mineral doesn't make a streak is it not a mineral?
Minerals with a hardness greater than around 7 on the Mohs hardness scale will not leave a streak on a standard unglazed porcelain streak plate. They will instead scratch and powder the streak plate.
What is the purpose of the plate?
A streak plate is used to determine the streak colour of a mineral. You take the mineral and scratch it against the streak plate, and it will create a coloured streak on the plate. The streak is not always the same colour as the mineral itself.
The calor a mineral leaves when it is rubbed across a plate?
Streak is the color of the finely powdered mineral when rubbed across a plate. Streak is one of the physical properties of minerals used to identify which specific mineral it is. Some minerals leave a completely different color streak than the original color of the whole mineral.
Why could the streak of corundum be difficult to determine?
The mineral corundum, with a Mohs hardness of 9, will be harder than a ceramic streak plate and therefore leave no streak.
How do you determine the streak of a mineral whose Mohs scale is higher than the streak plate?
You can determine the streak of a mineral whose Mohs scale is higher than the streak plate by either filing or crushing with a hammer before rubbing the sample on a streak plate.
What is used to find the streak of a mineral?
The streak of a mineral refers to the color left on a streak plate after rubbing a mineral across its surface. A streak plate can be as simple as the unglazed side of a porcelain tile. The streak is the mineral in a powdered form from abrasion with the hard, slightly textured surface of the unglazed porcelain streak plate. The streak color may differ from the color observed in a specimen. The streak is used as an aid in the identification of minerals.
What is a streak plate?
A streak plate is a surface of unglazed ceramic, used to find the true color of a mineral specimen by drawing the specimen across it. The color of the resultant powder is referred to as the streak or streak color of a mineral.
How do you identify minerals according to streak?
Minerals can be identified by their streak, which is the color of the mineral when it is broken down into a powder. To test a mineral's streak, a streak plate (usually made of unglazed porcelain) is used. The streak is usually compared to a streak color chart, which contains the colors of a variety of minerals. To test a mineral for its streak, take a small piece of the mineral and rub it on the streak plate. The resulting powder is then compared to the streak chart to identify the mineral. Streak is an important property of minerals because it is more reliable than the external color of the mineral. External color can be altered by impurities and oxidation, but the streak of a mineral does not change. Therefore, testing a mineral's streak is an effective way of identifying it.When identifying minerals according to streak, it is important to consider the following properties: Color - the color of the powder when rubbed on the streak plate. Luster - the shine of the powder when rubbed on the streak plate. Texture - the feel of the powder when rubbed on the streak plate. Opacity - the transparency of the powder when rubbed on the streak plate.By considering these properties when testing a mineral's streak, it is possible to identify the mineral accurately and quickly.
Why do some very hard minerals leave no streak?
Some minerals are harder than a streak plate and will therefore leave no streak or the powder of the ceramic streak plate.
What is the powder left behind on a streak plate called?
It is called a mineral streak.
