In a thread about "Off-limit minerals" - see here, Jenna commented on testing minerals by taste, which prompted me to reply with the first part of this blog, but it grew and rambled so off-topic for that thread, that I decided to make it my first Mindat blog post, and I have put it here.

I once worked in the field with someone who claimed to be able to distinguish phosphates/sulphates/arsenates by taste:

PO4 = somewhat soapy
SO4 = acidic
AsO4 = metallic/garlic

His rationale seemed to be that so little is needed for the taste buds to recognise these differences that even very slight solubility allowed the taste to be distinguished, and a good spit cleared the palate sufficiently to remove all but toxicologically insignificant traces of the above radicals and any associated metals. I never took him up on the challenge to see if I could learn the trick, and never did any follow-up analyses on samples "identified" by this method, so can't comment on how effective it was. I DON'T recommend it, but he is still alive almost 20 years later, and as far as I know, his tongue hasn't fallen out (although I know Tl is implicated in hair loss . . . ? ! ).

Regarding the OP, when I first started collecting minerals (mid 1960's), my mother (who was a nurse) was rather concerned to see some pieces of galena on my desk and commented that I ought to be careful with them and wash my hands after handling them, as they looked as if they contained a lot of lead, but she wasn't concerned about that nice lump of ruby-red rock (massive cinnabar!). I decided not to tell her about the realgar, orpiment and powdery scorodite I had.

Concerning radioactive minerals: Yes, I do keep my larger pieces of U minerals in a steel cupboard in the garage, and whenever I get them out, I leave them to air for a while after opening the boxes, before bringing them indoors or examining them closely, to allow any accumulated radon to disperse.

I spent some time back in the 1980's working on the lab side of U exploration projects, and frequently received samples for XRD analysis which consisted of crumbly and powdery secondaries. I remember one occasion when I had spent the morning preparing samples from some particularly dusty lumps of U-mineralised sandstone. I washed up, scrubbed my hands, and went for lunch.

In the afternoon, whilst the X-rays were running, I went into the darkroom to examine some specimens under the U-V lamps. When I switched these on, I was rather surprised to see lots of bright green fluorescent specks on my hands, and not only under my fingernails, but I wasn't too worried, since I reckoned that any grains which had survived a good scrubbing without being dislodged would have been unlikely to have come off whilst I was eating my sandwiches!

However, I did increase my scrubbing up time for a while after that, and got into the habit of holding any finger food with a piece of tissue rather than bare hands. We often used to eat in the labs in those days, and it was not unusual to see a mug of coffee, and a pie or a bag of crisps on the bench among the rock specimens. One year, we even prepared a Christmas dinner in the laboratory. (I wish I had taken photos of the sprouts boiling in a large beaked over a bunsen burner, the mince pies being heated in the clay-drying oven, and the sherry served in 50ml beakers). Later that afternoon, one of our senior officers chased a female colleague along a corridor, soaking her with a fire extinguisher, even though she was not on fire! We understood that his main justification was that it was a serious scientific experiment to demonstrate that thin silk fabric became transparent when wet, and so of course, we all paid full attention to the experiment, and considered his hypothesis well proven beyond any reasonable doubt. Irresponsible? childish? bullying? sexist? - perhaps a bit of each, but less paranoid, regulation-bound, and PC than we have become today, one hell of a lot of fun, and no-one got hurt; (even the girl in the silk blouse got her revenge.) If the PC thought police come after me, asking who was behaving in such a manner they're wasting their time; I'm not naming any names!

Anyone who has worked in laboratories for over 30 years will, I am sure have their fair share of similar anecdotes. I'll mention just one more here. Writing about the incident with the fire extinguisher reminds me of the time when another senior officer (actually the head of the section in question) walked into the rock slicing and polishing laboratory, lit up a cigarette, and dropped the match into a steel wastepaper bin. So far, so good. Except that the pile of damp tissues in the bin had not been wetted with water, but had been used to mop up paraffin from the polishing laps. Drop a lighted match into liquid paraffin and it will (probably) go out. Drop it onto a pile of loosely-packed paraffin-soaked tissue paper, and the results are spectacular; in a fraction of a second the flames reached the ceiling.

At that time there were a few screams to the effect of "You ******* idiot!", and someone put a lid on the bin. Result? fire extinguished, a few red faces and a ban on smoking in the laboratories. Today a similar incident would probably set off smoke & automatic fire alarms, prompting a full evacuation of the building, and in a laboratory, the alarm would probably be linked to the local fire station, resulting in an emergency vehicle and fire crew call-out, even if the fire had by that time been put out.

Yes, of course there were risks in setting off water fire extinguishers in close proximity to live electrical equipment, and running down a corridor with glass partitions whilst doing so, as there are in cooking, eating and smoking in laboratories, and also in handling dusty, toxic, radioactive, and asbestiform minerals, grinding silicates, and any field work, particularly in working quarries, mines, and at drill sites. But notwithstanding all that, I tend to the view that almost anything that is worth doing that is out of the everyday and gives one a buzz has an element of risk, whether it be driving at high speed, climbing moutains in winter, white water rafting, playing rugby, stalling a glider and putting it into a vertical dive, sailing on the ocean in a gale, free diving to almost 15 metres sans SCUBA, walking unarmed through African bush country, or going underground in old, partly flooded mines with rotting timbers and only one way out (all on my CV if you need to know!)

Part of the enjoyment is knowing what the risks are, making one's judgement as to whether they are worth taking for the purposes of enjoying the activity in question, or the potential achievment, and if they are, then going for it. I like to have control of what I am doing, and to be able to pause for thinking time. So for example, although I get vertigo, I was determined to go to the top level of the Eiffel Tower when I visited Paris, and I will manage a steep mountain scramble, and put up with considerable exposure (in the ridge climbing, not the hypothermal sense), and grit my teeth and abseil off a cliff, but I have drawn the line at bungee jumping. As for sky diving, I believe anyone who would willingly jump out of a perfectly serviceable aircraft, trusting their life to someone else's skill at stuffing an oversized handkerchief and a few hundred metres of string into a rucksack, must have a death-wish.

And as I said earlier, I do treat my radioactive and toxic minerals with a certain amount of caution and respect, and no, I don't attempt to distinguish sulphates frtom arsenates by taste, which brings us back to where we started.

Minerals to avoid? I am not too keen on handling villiaumite (soluble fluoride, toxic by skin absorption), but the only time I ever turned down the opportunity to purchase a rare mineral because of its potential toxicity was in my early days of mineral collecting. I was visiting Richard Barstow, and he showed me a specimen of vrbaite. Despite being fairly tolerant of handling heavy metals, I was a bit phased to be confronted with Tl, Hg, Sb and As, all in the same specimen, and I declined his offer. I regretted it later though, not only because I found out how rare it is, and at what a bargain price he had offered me that particularly good specimen, but also because that was the last time I ever saw him.

Carpe Diem.

Pete N.

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