If a mineral can be scratched by your finger nail, is it necessarily

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For something that a pure, crystalline mineral, yes, if your fingernail is scratching the surface it is softer than your fingernail in terms of Hardness.

That image is definitely Talc though, that's exactly what it looks like in nature, before being processed into a powder.

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I just picked a google image photo of a mineral that is softer than the fingernail. The pic I just took is what I'm talking about. Sorry it's not super clear. I can definitely scratch it with my fingernail.

>>8640713
heh. I went ahead and chose softer than fingernail which was correct. Score 55/66. :-\ I'm not geologist. Hopefully, next weeks rock lab is a little easier.

>>8640749
and I just realized my kit came with a piece of glass. Save my soul Kek,

Remember in a pinch that the underside of the lid of your toilet tank is a streak plate.

>>8640695
Legit question: how is the Mohs hardness scale determined? I've used it in petrology classes but none of my professors or TAs explained beyond "a scale for hardness".
Like, is a 2 on the scale twice as hard as a 1 or is it logrithmic? Can hardness even be described mathematically/physically or is it just "Talc is really soft, that's a 1. Diamond is really hard, that's a 10"?

If someone could even point me as to what to Google to find out more I'd be very appreciative.

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>>8640802
I dont believe it's logarithmic. It just implies "if its a 3, it can scratch a 2."

Pic related. It's not a straight slope, but it's not logarithmic either

>>8640802
Mohs just picked 10 standard minerals and numbered them. A 5.5 can scratch a 5 but not a 6. It's a useful identification tool.
'Hardness' has different definitions in different fields. Just google the term.