Shiny rocks that sparked the mad South African diamond rush this month were actually just quartz

Originally published at: Shiny rocks that sparked the mad South African diamond rush this month were actually just quartz | Boing Boing


But think of all the free healing that was done by those crystals? Amazing…


I’m certainly not expecting there to be geologists on hand; and I can hardly fault the desperate for being hopeful; but from what I’ve heard of the properties of diamonds I’m a little surprised that confusion with quartz held up for long.

Diamonds have(by the standards of solids, heatpipes and similar sneaky composite solutions can do very well) downright spooky thermal conductivity, not necessarily noticeable with small diamonds; but a large one should really make its presence known if it is either warmer or cooler than your hand.

There’s also the similarly extreme refractive index; obviously they don’t come out of the ground with a brilliant cut; but if they are at least reasonably transparent that should be noticeably different than other similar looking minerals.

A scratch test wouldn’t necessarily be decisive; both diamond and quartz are pretty hard vs. glass or other test materials likely to be widely available and non-destructive enough that people would dare try them.


Some of the poor quality images that were shared made me instantly think they were more likely to be rock crystal which has much the same appearance in the rough as diamond. The trigonal crystallography of quartz and (as you say) different thermal properties of diamond aren’t so well known, so I can understand why people might have thought they’d found stones.

If they are good quality rock crystal then they might have some value, but only a fraction of that of diamond.


IIRC, diamonds are found in kimberlite, not just in the dirt.

I wanted to take the kiddo to a quartz mine in Arkansas, and hopefully will in the next year or so.

Quartz ain’t diamond, but possibly gold! While hiking around the cascades (particularly within a few miles the ghost town of Monte Cristo WA (which had ewww trump connections, but that’s a story for a different time)) one can still see veins of quartz in the rock out-croppings which have been carefully followed down to some supporting ground and there will be an attempt at mining for gold. They knew that quartz and gold uh… (no geologist i) co-sediment. I remember one such mine which had a Christian symbol carved into the rock alongside the quartz vein - someone wanted Jesus to guide their pick and shovel.


Kimberlite and Alluvial. Alluvial presents… as just dirt.

Diamonds are cubic so counting sides helps but isn’t conclusive - you can do a scratch test but would need corundum or something else with a 9 hardness - even that’s not conclusive.

You can get a diamond tester - but that’s way beyond the means of any of these people - or wait for a lab - which is what they did.


It’s possible that the folks digging had never handled or closely examined a diamond.

That could well be; but given how common quartz is I’d then wonder what led to the conclusion that it was a diamond, if they have no experience with diamonds but have probably seen quartz before. That could just be the hope kicking in, I suppose.

I’d certainly imagine that they’ve never been close to a big diamond; that’s reasonably unusual even in places where small-ish diamonds are considered pretty prosaic for jewelry purposes; but I’d also suspect that, with the find not terribly far from places where real diamonds do crop up quite regularly, some sort of dealer/broker/middleman character who has at least evaluated small diamonds would have been on the scene fairly quickly.


Yes, I have seen samples of gold running through quartz. So cool looking.

Ah, learned something new.

But IIRC quartz is a 7, so if you can scratch it with something similar, you would know its not diamond. The fact these were HUGE would be a tip off - as diamonds that large are exceptionally rare.

But yeah, they don’t call pyrite fools gold for nothing. I’m an amateur and still have trouble IDing minerals. Most people have zero clue other than if a rock is pretty or not.


It’s trivial to tell once you start to cut the gem - but raw gems and minerals are tough to tell - Africa is so ripe with both it’s hard to fault people for getting excited.

I doubt I’d be able to find any of this stuff in the wild without a ton of experience myself - and I suspect that quite a bit of incredible wealth goes undetected around humanity as a whole due to the inability to identify it - that’s much of what makes those things valuable to begin with…


Finding stuff in the wild is the most fun.

I am still kicking myself that I was in Duluth a whole week before I realized there were agates all over the place.

I want to get back up there and to go Yooperlite hunting.


If they had been real diamonds, the excitement would have driven the farmer to suicide (by shooting himself five times in the back of the head immediately after willing the land to deBeers) inside of a week. Or at the very least, some mineralogical reason would have been discovered why these weren’t the valuable kind of diamond.

Random good fortune was never going to be allowed to be that random.


My first thought is to say “quartz. . . that’s what De Beers wants you to think.


Next up the Great “Fool’s Gold” Rush!

Year from now, people will still be traveling there and digging and there will be entire Internet groups devoted to proving that there actually were diamond but DeBeers or such came in and fooled everyone so they could reap the harvest. :slight_smile:

Nothing blinds a person to facts more than baseless hopes.

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Alluvial diamonds are also a thing, they are found where diamonds have been washed out of kimberlite. They make up a sizeable fraction of South Africa’s and all of Namibia’s diamond production.

Quartz is common, but rock crystal which is just colourless quartz is quite rare, especially in well-formed sizeable crystals. Rate enough that it has some value as a semi precious stone - cut well, rock Crystal has some of the glitter and refraction associated with diamond and can fetch appreciable prices.

In the rough, the two are quite similar to the untrained eye and the appearance of a big, colourless crystal in a country known for diamond is going to get anyone’s hopes up.

Diamonds are sometime found in the soil in South Africa, and some of those have been big and found in quantities. So it wasn’t impossible, only unlikely given this area’s geology - but again, that is specialist knowledge.

When you have nothing, hope is all you can rely on.

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