Want this question answered?
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.
StreakColor of the mineral when it is powdered.Grind a small amount of a mineral into a powder on a porcelain streak plate and determine the color of the powder.
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.
The term for this that I've always heard is "streak".
Streak tests are used to identify minerals. Rubbing a mineral specimen against unglazed white porcelain, or finely powdering it and examining the powder against a white background, is a useful diagnostic test in some cases. Eg. hematite, a black mineral that looks much like many other black minerals, has a distinctive red streak.
color
Color is what you observe when you look at a mineral. Streak is the color of the mineral when in a fine powder form. This can be observed by drawing a sample of the mineral over an unglazed porcelain tile and noting the color of the line left on the tile.
streak
The mineral is sratched on a unglazed white title the powder left is the is the color of the minerals streak which is used to find the name of the mineral and identify it.
Which mineral leaves a green-black powder when rubbed against an unglazed porcelain plate?
streak.
You would observe the true color of a mineral as represented by the powder created by abrasion with the 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.
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.
StreakColor of the mineral when it is powdered.Grind a small amount of a mineral into a powder on a porcelain streak plate and determine the color of the powder.
The color of the powdered form of a mineral is called
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.