On a more “licking” note than an “LSD” note - in geology 101, had a group exam where we had to identify mineral samples. Group spent 50% of the total time waffling on deciding how to identify the last two samples - salt and quartz. We knew one was one, and the other the other. Finally got tired of arguments about clarity or cleavage or whatever other nonsense we had in that elective. I had places to be. Licked one. Then the other. Second one was salt. Probably wasn’t the first college student to lick those samples either.
Licensed Professional Geologist here, and licking is a totally valid method for distinguishing between mineral hand samples that have very similar properties otherwise. For instance, halite (NaCl, aka table salt) and sylvite (KCl) are isomorphous, which means they have the exact same crystal structure and are very difficult to distinguish using traditional methods. Halite tastes like salt, but sylvite makes your tongue tingle when licked. Our mineralogy professor told is it’s the only reliable way to differentiate the two without actual chemistry analysis.
Wouldn’t a scratch test have worked just as well? Quartz is extremely hard, halite is relatively soft. Scratch one against the other, and whichever one is damaged is salt.
On a more “licking” note than an “LSD” note - in geology 101, had a group exam where we had to identify mineral samples. Group spent 50% of the total time waffling on deciding how to identify the last two samples - salt and quartz. We knew one was one, and the other the other. Finally got tired of arguments about clarity or cleavage or whatever other nonsense we had in that elective. I had places to be. Licked one. Then the other. Second one was salt. Probably wasn’t the first college student to lick those samples either.
Licensed Professional Geologist here, and licking is a totally valid method for distinguishing between mineral hand samples that have very similar properties otherwise. For instance, halite (NaCl, aka table salt) and sylvite (KCl) are isomorphous, which means they have the exact same crystal structure and are very difficult to distinguish using traditional methods. Halite tastes like salt, but sylvite makes your tongue tingle when licked. Our mineralogy professor told is it’s the only reliable way to differentiate the two without actual chemistry analysis.
Licking is a chemical analysis, albeit a crude one
I wouldn’t call a chemical touch sensor optimized by eons of evolution to differentiate molecules from one another crude.
In some ways it’s no more crude than looking at it, right?
Couldn’t you just scratch one with your keys?
Between halite and quartz, absolutely. Halite and sylvite have the Moh’s hardness of 2, so your keys would scratch both.
Nope, geologists are commonly associated with licking rocks, and basically for the reason you’ve shared.
Wouldn’t a scratch test have worked just as well? Quartz is extremely hard, halite is relatively soft. Scratch one against the other, and whichever one is damaged is salt.
Rub it against your phone screen and you’ll find out pretty quick
It scratches at a level salt, with deeper grooves at a level quarts
Hell, I had a geology lab where we were explicitly told we’d have to identify minerals by taste.
Unfortunately one of the other criteria was testing how a mineral reacted to acid… Which was listed higher on the worksheet…
Didn’t taste that bad, as far as acids go.