By rubbing mineral against a piece of porcelain tile, the objective of the test is to observe the hardness of the mineral.
That procedure tests the streak of the mineral. Oddly, the streak color of some minerals are different from the mineral's color.
The test described is called a streak test, and indicates the true color of a mineral as observed in a powdered form.
The test is called a streak test and it leaves a powdered form of the mineral on the porcelain. The powdered mineral reveals the true color, of the mineral specimen, which may or may not match the color of the specimen.
This is called a streak test, and is done using the back of an unglazed white porcelain tile. It reveals the color of the mineral when powdered, which is occasionally quite different and a good identifier. Eg. hematite is black to the eye, but it's streak is red.
Which mineral leaves a green-black powder when rubbed against an unglazed porcelain plate?
You're looking for the word "Streak". This means you are testing for the 'raw' colour of the powered mineral, which ceases to have a crystalline structure. This allows for the comparison of minerals that have some variability of colour (such as hematite, which can be a dark red, black, or shiny-silvery colour). This is a more accurate way of describing an unidentified mineral than to use it's physical colour appearance, and can be used to identify some minerals. Use caution when using this method, as some minerals are in fact HARDER than the porcelain(which has a Moh's hardness of about 7), and the porcelain will come off onto the mineral producing a false 'white' streak.
You identify minerals through a streak test. This involves taking the tile and the mineral to be identified and rubbing them together. This produces a colored streak on the tile, which can be used to identify the mineral. Consult a field guide for specific colors.
It is called the mineral's streak, an aid in identifying the mineral.
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.
Porcelain, as the name suggests.
The color left by a mineral on unglazed porcelain would be its streak.
Mineral samples can be scraped across the bottom (i.e., the unglazed side) of a tile to create a colour streak which is characteristic of the mineral. Note that it takes more than a colour streak to identify a mineral. Many minerals have the same colour streak. Other characteristics such as the hardness and density will also need to be determined in order to positively identify a mineral.
You identify a mineral by it's physical properties.
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.
By rubbing a mineral against a piece of unglazed porcelain tile From Prentice Hall textbook: Inside Earth
I'm honestly not sure what your instructor expects there. The name of that procedure is the "streak test", but that doesn't quite fit in the sentence.
How can you identify an unknown mineral sent
The worst way to identify a mineral is by tasting it. When you are classifying a mineral by tasting it doesn't do much. So taste is the worst way to identify a mineral.
This is a test of the mineral's true color, referred to as the 'streak' color.
the least accurate way to identify a mineral
A white, unglazed porcelain streak plate and a sample of the mineral.