Hacker News Reader

Comment by TGower | Hacker News Reader

It still amazes me that the rare shiny rocks humanity has appreciated for thousands of years also turn out to have amazing properties even compared to the synthetic materials we are now capable of creating. It's still the hardest material we have measured. It is the best thermal conductor, even though it's an electrical insulator.

View on HN

It is a very good thermal conductor, but not the best. At low temperatures, copper is better. At very low temperatures, helium is much better.

Superfluid helium's maximum thermal conductivity is roughly 100x diamond's maximum!

Neat! At around the temperature of liquid water, it's still about five times as good as copper.

So.

1. They can grow diamonds.

2. Diamonds are good for heat conduction in the liquid-water-temperature range.

3. Diamonds are good for electrical insulation.

Where are the full diamond water blocks for the water cooled RGB bling computers?!?

It's murderously hard to machine.

True.

I guess it is a matter of what shape is grown. For some reason I thought a flat plate being sublimated onto but I honestly don't know.

But if you can get a flat plate made from diamond then a clever design should be able to use that.

But never mind the practicality - as long as it doesn't leak - then marketing could have a field day...

>Superfluid helium's maximum thermal conductivity is roughly 100x diamond's maximum!

Never thought about this before. Would that mean that heat propagates much more quickly? Possibly even approaching the speed of sound of the material?

Slide 12. Pretty much yeah. https://indico.cern.ch/event/1541024/attachments/3055157/540...

You can kind of isolate the different vibrational modes and their corresponding energy transmission. "Phonons" are basically sound waves (the particle analogue), labeled in figure 2: https://www.nist.gov/system/files/documents/2019/07/12/dcs_2...

Thermal conductivity measures the heat flux given a temperature gradient. That is, how fast heat energy flows across a surface, given a certain temperature gradient across it.

It has nothing to do with the velocity of the heat carriers themselves (phonons, or charged particles).

E.g. phonons always travel at the speed of sound, in any material.

They make nice (and expensive) tweeters, too.

https://www.madisoundspeakerstore.com/diamond-dome-tweeters/...

> even compared to the synthetic materials we are now capable of creating

Aren't like almost all commercially used diamonds these days synthetic as well? As far as I can tell, other than just for the sake of them being "natural" or for having weird impurities that add color to them (read as: subjectively better to some people), no one wants/needs natural ones anymore.

We can recreate lots of things, but almost always appreciate the true version better. It’s why it’s cooler to see the Mona Lisa than to see a poster print of it.

Why? As far as I can tell, other than just for the sake of the view being “natural” or having some weird color issues due to time and radiation and oxidization, nobody wants/needs the actual painting anymore.

Reason: because even when it’s identical or even inferior, the touch of nature is just… nice.

I think you just described the placebo effect!

Unfortunately, as much as I'd like to pick and choose when it effects me, I am a mere mortal, as are many I believe.

A painting has a 3 dimensional texture to the paint, while a poster is inevitably flat. Different paint compositions will also reflect light differently, while a poster won't.

So, yeah, having the real painting has additional value.

I wouldn't pay much for a painting anyway. I have several paintings and posters up on the walls, and they're interesting for a time, and then I just don't see them anymore. They're just part of the wall.

One thing that plebians will never appreciate about the true value of original, legitimate artwork is the ease with which one can use them to launder vast amounts of money

For some things maybe.

For gemstones, nah I really don't want blood diamonds.

To be clear, you acknowledge the natural version would be better, but the controversy and conflict surrounding it is what actually turns you off. This has no effect on my argument that people prefer real things.

Naturally, if you said “you can have the Mona Lisa but only if someone is murdered in the process”, reprints of it would be very popular.

>To be clear, you acknowledge the natural version would be better

No, not at all. I prefer the artificial ones. Any size you want at a much lower cost. No massive amounts of mining. The fact they don't cost some indigenous kids lives is a well earned bonus.

It is you with a strong attachment to the idea that natural is somehow better.

> Any size you want at a much lower cost

In this case, I'll have the five million carat please. What will that run? :)

Is “synthetic” the right word?

I thought they are “lab grown”.

(Synthetic implies non-real, when at a molecular level the lab grown are 100% real)

I think synthetic ~ synthesized in this context, as opposed to "not real".

Sense 4a1 here, not 4c: https://www.merriam-webster.com/dictionary/synthetic

Unrelated, but does anyone else find the adjacent (4b) definition of 'synthetic' to be unusually unusual, in a way few definitions in a dictionary are?

Without anything redacted, definition 4b is "devised, arranged, or fabricated for special situations to imitate or replace usual realities"?

Seems okay to me

I guess I just think of "synthetic grass", like AstroTurf and associate "synthetic" with non-real.

I've thought about this at times. How convenient that things seem to work out that way! Though I wonder if it's more just a bias. All the very impressive things you can make from the abundant materials have already been made. Like, say, all of life?

Blue pigments used to be extremely rare and precious. Then some chemists found the infinite blue glitch.

Also the convert energy into aluminum glitch.

Can you elaborate? Sounds cool

Up until electricity abundance, aluminium was almost unknown to most as refining it requires lots of electricity. Aluminium ore is very abundant too but we didn't know what to do with it.

Prior to this process, aluminum basically didn’t exist naturally and was incredibly hard to refine from bauxite.

It’s wild how not long ago aluminum was an unbelievably rare, valuable metal, and now it’s ubiquitous and cheap.

The intense electricity requirement is also why recycling aluminum is not just an environmental activity: it’s a profitable one.

https://en.wikipedia.org/wiki/Hall%E2%80%93H%C3%A9roult_proc...

And the convert energy into fertilizer glitch.

Diamonds are crystals, like silicon Nothing wrong with liking shiny rocks, but they aren't that rare and we can generally produce them. Materials have properties. Understanding the properties generally gives us leverage to use them in our own benefit.

> It's still the hardest material we have measured.

Can't believe this statement hasn't caused other nerds to crawl out of their holes to correct it yet, so here I go: acshually...

We know about Lonsdaleite, which packs its structured in hexagons rather than the usual cubic forms of diamonds.

... too bad its natural occurance is always somewhat spoiled and it doesn't reach its full potential in nature in any meaningful size, as far as we could observe.

Lonsdaleite looks like it should be harder than diamond based on simulation data, but we haven't actually measured a piece of Lonsdaleite that is harder than diamond.

Reply on news.ycombinator.com