neural
starting to spend too much on rocks
Member since November 2019
Posts: 114
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Post by neural on Apr 19, 2021 22:43:00 GMT -5
So, I'm slowly starting to try and learn a little about rock identification. Much as I love geology, my memory has never really lent itself to being able to quickly identify stones with any remote hint of accuracy just by looking at them.
Among the means of helping identify a stone, are things called streak plates. Drag the rock across the plate, and see if it leaves a streak, and what color said streak is.
What I want to know is this: I read that streak plates are made of ceramic material. Doesn't that mean they have a relatively low hardness? Are they intended to be one time use disposable items? Or do you do some form of scratch test on a stone first to determine that it won't wreck your streak plate?
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stefan
Cave Dweller
Member since January 2005
Posts: 14,094
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Post by stefan on Apr 20, 2021 18:09:52 GMT -5
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irlcjrohr
starting to spend too much on rocks
If it does not melt, polish it.
Member since April 2020
Posts: 123
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Post by irlcjrohr on Apr 20, 2021 21:20:02 GMT -5
I reuse my plates. I use them more for viewing the color of the streak rather than scratch test. The mineral has to be softer than the streak plate for it to work. Calcite is White and quarts is harder than the plate so it leaves no streak. geology.com/minerals/streak-test.shtml
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