Most scratches from fingernails leave red marks where the scratch occurred.
Your nail is 2.5 so the rocks you can scratch are, Gypsum and Talc.
No, you cannot get HIV from a fingernail scratch. HIV is transmitted through specific bodily fluids, such as blood, semen, vaginal fluids, and breast milk. Casual contact like a fingernail scratch does not pose a risk for HIV transmission.
Scratch.
you can scratch talc becuase it is the softest mineral on the moth scale.
Talc is a very soft mineral, ranking as 1 on the Mohs scale of hardness, and your fingernail is harder at around 2.5. This means your fingernail can easily scratch talc due to the difference in hardness levels.
The most commonly known mineral that can be scratched with a fingernail is talc.
To determine if a scratch can be removed rather than having to refinish your vehicle, run your fingernail LIGHTLY over the scratch. If your fingernail catches it cannot be removed. If your nail doesn't catch the scratch can be removed by buffing the scratch with a compound. (if the scratch is still there, try sanding with fine grade sand paper 800grit or higher then repeat buffing)
GypsumHardnessMineralAssociations and Uses1Talc (Softest)Talcum powder. (can be scratched by a fingernail.)2GypsumPlaster of paris.Gypsum is formed when seawater evaporates from the Earth's surface. (May be scratched by a fingernail or by a copper coin.)3CalciteLimestone and most shells contain calcite.(Can be scratched by a steel pocket knife or sometimes a copper coin. Will scratch a fingernail, may scratch a copper coin.)4FluoriteFluorine in fluorite prevents tooth decay.(Can be scratched by a steel pocket knife. Will scratch a fingernail and a copper coin.)5ApatiteWhen you are hungry you have a big "appetite".(Can be scratched by a steel pocket knife. Will scratch a fingernail and a copper coin.)6OrthoclaseOrthoclase is a feldspar, and in German, "feld" means "field".(Will not scratch glass but will scratch steel blades, copper coins & fingernails.)7Quartz (Will scratch glass, steel blades, copper coins & fingernails.)8TopazThe November birthstone. Emerald and aquamarine are varieties of beryl with a hardness of 8. (Will scratch glass, steel blades, copper coins & fingernails.)9CorundumSapphire and ruby are varieties of corundum. Twice as hard as topaz.(Will scratch glass, steel blades, copper coins & fingernails.)10Diamond (hardest)Used in jewelry and cutting tools. Four times as hard as corundum.(Will scratch all of the above.)
The mineral that you can't scratch with your fingernail but can be scratched by a copper penny is calcite. Calcite has a hardness of about 3 on the Mohs scale, while fingernails have a hardness of around 2.5. A copper penny, which has a hardness of approximately 3.5, can easily scratch calcite.
Talc and gypsum are two minerals that can be scratched with a fingernail due to their low hardness on the Mohs scale.
use clear fingernail polish (or colored if you have to) and apply it over the bite. the red bugs attach at the surface of the skin and you need to stop their air supply to kill them. if you scratch them until the surface is red and swollen it will only only prolong their life under the skin.
Acorn squash is ripe for harvesting when the skin is hard and cannot be easily pierced with a fingernail, and the color is deep and consistent.