A mineral or other material with a higher hardness number can scratch anything with an equal or lower number. Thus, a copper penny can scratch calcite, gypsum and talc, while a fingernail can scratch only gypsum and talc. A piece of quartz can scratch fluorite but it cannot scratch topaz.
What mineral is not scratched by a fingernail but is scratched by a knife?
| mineral Mohs hardness observations on the minerals | talc 1 very easily scratched by the fingernail; has a greasy feel | gypsum 2 can be scratched by the fingernail | calcite 3 very easily scratched with a knife and just scratched with a copper coin | fluorite 4 very easily scratched with a knife but not as easily as calcite |
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What mineral is not scratched by a fingernail?
| Mineral Hardness | Calcite | INTERMEDIATE Mineral cannot be scratched with a fingernail but can be scratched with a steel nail. | Gypsum | SOFT Mineral can be scratched with a fingernail |
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Which mineral is the softest and can be scratched by your fingernail?
Notice that talc is the softest mineral, while diamond is the hardest. You can easily scratch talc with your fingernail. Apatite, a mineral in the middle of the hardness scale, can scratch glass but can be easily scratched by a knife.
What is the hardness of a mineral if it can't be scratched by your fingernail but can be scratched by a steel nail?
6.5 Hardened Steel File – If a hardened file won't scratch your mineral, it's very hard and has a hardness greater than 6.5. Usually above this level, you need to find a piece of mineral to scratch your mineral to determine the hardness.
Can gypsum be scratched by a fingernail?
Your fingernail can scratch gypsum , which has a hardness of 2, but not calcite, with a hardness of 3. Your fingernail thus has a hardness of about 2.5. Once the specimens are ranked by hardness, show that softer ones cannot scratch harder ones. Thus talc cannot scratch calcite, etc.
What is the only mineral that can scratch a diamond?
Mohs Hardness Scale
Diamond is the hardest mineral; no other mineral can scratch a diamond . Quartz is a 7. It can be scratched by topaz, corundum, and diamond.
Can Topaz be scratched by a fingernail?
The numbers on the scale classify minerals only by their hardness. That is, topaz is harder than quartz, which is harder than feldspar. ... Substances with a hardness of 2 or less may be scratched by a fingernail .
What mineral can be scratched by a knife?
| mineral Mohs hardness observations on the minerals | apatite 5 scratched with a knife with difficulty | orthoclase 6 cannot be scratched with a knife, but scratches glass with difficulty | quartz 7 scratches glass easily | topaz 8 scratches glass very easily |
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Does a fingernail scratch Muscovite?
| 1) Tacl 6) Orthoclase | 5) Apatite 10) Diamond |
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Which mineral can be scratched by a fingernail?
| 10 Diamond | 5 Apatite (knife blade or nail – 5, window glass – 5.5) | 4 Fluorite | 3 Calcite | 2 Gypsum (fingernail – 2) |
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What can fingernails scratch?
A fingernail can scratch only a few minerals . When the test fails, the unknown mineral is then harder than your fingernail. You should logically ask, “How much harder than your fingernail?” and proceed to the next harder object, the penny. Suppose the unknown mineral easily scratches the penny.
Can a fingernail scratch glass?
3 Answers. Responding to this specific part of the question: “scratches caused by fingernails or creating worn out areas of the screen, due to frequent use.” Although many things can and will degrade the coating (oleophobic or other), the gorilla glass itself will not be scratched by fingernails .
What is the strongest rock in the world?
The strongest rock in the world is diabase , followed closely by other fine-grained igneous rocks and quartzite. Diabase is strongest in compression, tension, and shear stress. If mineral hardness is the determining factor of strength then diamond is technically the strongest rock in the world.
What is the softest mineral on Earth?
Talc is the softest and diamond is the hardest. Each mineral can scratch only those below it on the scale. Look at the scale below – click on the pictures to find out about each mineral. You can easily test for hardness.
What is the hardest stone in the world?
Diamonds are the hardest stone, while talc (for example) is a very soft mineral. The scale by which the hardness of minerals is measured is the Mohs Hardness Scale, which compares the resistance of a mineral to being scratched by ten standard reference minerals that vary in hardness.
