Table of Contents
Can a nail scratch feldspar?
Terminology. Soft – can be scratched by a fingernail, Mohs’ 1-2; If a mineral cannot be scratched by a knife blade but can be scratched by quartz then its hardness is between 5 and 7 (stated as 5-7) on Mohs scale. A relative hardness value of 6.5 means that the mineral could scratch orthoclase (feldspar) but not quartz …
What minerals can scratch a copper penny?
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 minerals can scratch a glass plate?
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 |
|---|---|
| 2 | Gypsum, CaSO4-2H2O |
| 1 | Talc, Mg3Si4O10(OH)2 |
| HARDNESS | FAMILIAR OBJECT |
| 5.5 | Glass plate, knife blade |
Can feldspar scratch itself?
As you can see, diamond is a 10 on the Mohs Hardness Scale. Diamond is the hardest mineral; no other mineral can scratch a diamond. Quartz is a 7….Mohs Hardness Scale.
| Hardness | Mineral |
|---|---|
| 5 | Apatite |
| 6 | Orthoclase feldspar |
| 7 | Quartz |
| 8 | Topaz |
What can scratch a penny but not glass?
Also if a penny can scratch a mineral it rates a 3, a fingernail is 2.5, knife blade 5.5, glass 5.5 and steel file 6.5. Talc rates a one on the scale meaning that it is the softest mineral and can be scratched by just about anything.
What can be scratched by a copper penny but not a fingernail?
If you are able to scratch your specimen with the penny but not with your fingernail, it has a hardness between 2.5 and 3.5. If the specimen does not scratch with a penny, try a knife blade or glass. A diamond can only be scratched by another diamond. One last test that is commonly used is called a streak test.
What will scratch feldspar?
This is because feldspar is a 6 on the scale, and quartz is a 7. Some objects that are rated as a 7 in hardness, like quartz, are black opal, bloodstone, jasper, onyx, tiger’s eye, carnelian, chalcedony, citrine, and amethyst.
What mineral will scratch glass but not streak plate?
Hardness
| mineral | Mohs hardness | observations on the minerals |
|---|---|---|
| fluorite | 4 | very easily scratched with a knife but not as easily as calcite |
| 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 |
Can you scratch a diamond with a knife?
No, a knife cannot scratch diamond. Diamond is much harder than a knife, even a ceramic knife. However if you put a lot of pressure at the wrong angle, you can crack a diamond. The crack can be shallow and look like a scratch.