Table of Contents
What minerals leave a white streak?
| Streak Colors of Common Minerals | |
|---|---|
| Andalusite | White or colorless (hardness is about the same as the streak plate). |
| Titanite | White. |
| Topaz | Colorless (harder than the streak plate). |
| Tourmaline | Colorless (harder than the streak plate). Specimens often fracture, shedding small particles. |
What minerals leave a green streak?
| TABLE 2 MINERALS WITH NON-METALLIC LUSTER | ||
|---|---|---|
| Name | H | Streak |
| Dolomite | 3 – 3.5 | white |
| Malachite | 3.5 – 4 | pale green |
| Sphalerite | 3.5 – 4 | light yellow to brown |
Why is a mineral’s streak different from its color?
It mostly has to do with the fact many minerals are partially translucent. Trace impurities or even crystal structure can dominate the color of a translucent material but when ground in to a fine powder (streak) they can no longe do so and you can see the true color.
What mineral leaves a red streak?
Hematite, which is black in appearance, leaves a red streak which accounts for its name, which comes from the Greek word “haima”, meaning “blood.” Galena, which can be similar in appearance to hematite, is easily distinguished by its gray streak.
Is quartz harder than the streak plate?
The simplest way to make a powder from a mineral sample is to grind the mineral on a small rectangular piece of unglazed ceramic called a streak plate. Streak plates have a Mohs hardness of around 7, but be sure to check your streak plate against a piece of quartz (hardness 7) because some are softer and some harder.
What mineral has a yellow streak?
gold
Streak is useful to distinguish two minerals that have the same color, but a different streak . A fine example is distinguishing gold, which has a yellow streak, and pyrite, which has a black streak.
What mineral has a hardness of 3?
calcite
Hardness
| mineral | Mohs hardness |
|---|---|
| calcite | 3 |
| fluorite | 4 |
| apatite | 5 |
| orthoclase | 6 |
What mineral has pink streak?
feldspar
A rock-forming mineral with a pink or pinkish color is almost certainly feldspar.
What is the difference between a mineral’s streak and color and why is streak more reliable for identification?
Streak is the color of a mineral’s powder. Streak is a more reliable property than color because streak does not vary. Minerals that are the same color may have a different colored streak. Many minerals, such as the quartz in the Figure 3, do not have streak.
What color streak would real gold leave on sandpaper?
Yellow-gold pyrite has a blackish streak.
Can a penny scratch glass?
If the glass plate scratches the mineral, the glass plate is harder than the mineral. Hence, the hardness of the mineral is less than 5.5 (H<5.5). Try to scratch the surface of the glass plate with a fresh corner of the mineral….
| HARDNESS | REPRESENTATIVE MINERAL |
|---|---|
| 5.5 | Glass plate, knife blade |
| 3 | Copper penny |
| 2.5 | Fingernail |
Which type of minerals do not give a colored streak?
A mineral with a white or colorless streak will not leave a visible streak on a streak plate. Swipe the mineral against the streak plate, but not hard enough to damage it. The color of the powder that results on the streak plate is the streak color.