Telling a real diamond from a fake?

[birdman]

If someone doesn't tell you which is which... none.

The price is about ten times lower for a cultured vs natural diamond.

Yup...hence the whole "it's artificial" stigma which really bothers me...it's a diamond...who cares if it was dug up, or made in a lab, if it's tetrahedral carbon crystal, it's a diamond.

The fluorescence levels of synthetic and natural can be different depending on processes, as can isotopic ratios, but really...who cares?

[zxcvbob]

Yup...hence the whole "it's artificial" stigma which really bothers me...it's a diamond...who cares if it was dug up, or made in a lab, if it's tetrahedral carbon crystal, it's a diamond.

The fluorescence levels of synthetic and natural can be different depending on processes, as can isotopic ratios, but really...who cares?

I'd prefer a laboratory diamond -- I know it wasn't mined using slave labor or helping to fund African warlords.

[Monkeyleg]

Well, it's not a real diamond. I took it two two jewelers and both said the same thing. They put some little device with a probe to the "stone", and it indicated it wasn't a diamond.

At the first store, I told the young lady behind the counter to just toss it in the wastebasket, which she did. As I walked out, I saw her from the corner of my eye take the stone (or whatever it is) out of the wastebasket and over to a work area. I gave it a couple of minutes, then went back in the store. Another woman was at the counter and I told her I had an idea for a practical joke to play on my wife, and would like the fake diamond from the trash. She rummaged around and couldn't find it, then said, "oh, Tammy has it over there", pointing to a table with a microscope and other gear.

I couldn't figure out why she'd be doing that, but it made me suspicious, so I took it to a second store just to be certain. It still didn't change into a diamond in that time.

I left it with the cute young lady in the office at the gym just in case someone is looking for it. Besides, it gives me another excuse to talk to her. (Actually, I look for excuses for her to finish the conversation and walk away. I just love watching her walk away ).

[230RN]

Marginally off-topic:

At the first store, I told the young lady behind the counter to just toss it in the wastebasket, which she did. As I walked out, I saw her from the corner of my eye take the stone (or whatever it is) out of the wastebasket and over to a work area.

That kind of thing happens with lotto-type tickets.  Clerk will run the ticket and say it's not a winner, you tell them to chuck it, and they retrieve the ticket when you leave and pocket the winnings.  Doesn't even have to be a big winning ticket.



Terry, 230RN

[RevDisk]

What's the difference between real and artificial?

Artificial one doesn't have flaws.

If made correctly (ie not intentionally downgraded), there is no difference except the artificial is likely better quality. But I believe artificial stones are supposed to be doped to differentiate the two.

[brimic]

With a real diamond with flaws, it might be possible to find the owner of the diamond. Jewelers 'map' the flaws in the stones.

As far as distrusting evaluations...

Several years back I wanted to pawn an old engagement ring given back to me by an old fiance so I could buy a rifle (should have just bought a rifle in the first place instead of an engagement ring) .
In a nearby town, there were two pawn shops about a block apart.
Pawn shop owner #1 examined the ring and gave me a price that seemed like a real lowball price, so I left and went to the other shop down the block, who gave me a price about $5 lower. I walked back to pawn shop #1 and they guy there greeted me by saying "I knew you'd be back."
I turned around and walked out and didn't go back. It felt like the two shops were in cahoots with eachother, probably #1 phoning #2 and telling him there was a mark on the way over with a engaement ring with $XX offered.

[Tallpine]

I left it with the cute young lady in the office at the gym just in case someone is looking for it. Besides, it gives me another excuse to talk to her. (Actually, I look for excuses for her to finish the conversation and walk away. I just love watching her walk away  ).

So you won't ask her out for coffee but you're giving her diamonds 

[seeker_two]

So you won't ask her out for coffee but you're giving her diamonds  

Maybe you could skip the drama and just start paying her alimony now?.....

[Regolith]

Marginally off-topic:

That kind of thing happens with lotto-type tickets.  Clerk will run the ticket and say it's not a winner, you tell them to chuck it, and they retrieve the ticket when you leave and pocket the winnings.  Doesn't even have to be a big winning ticket.



Terry, 230RN

In Orygun, all the lotto tickets have UPC codes on the back, and the places that sell them usually have a scanner you can use to see if it's a winner or not. Helps prevent that sort of thing.

[erictank]

In Orygun, all the lotto tickets have UPC codes on the back, and the places that sell them usually have a scanner you can use to see if it's a winner or not. Helps prevent that sort of thing.

They've had those on the self-service machines here in VA for a few years now.  You can even choose to redeem winning tickets (up to a certain, likely-fairly-small value which I do not know) right at the machine - as long as you want to buy more lottery tickets/scratcher tickets.  But it'll tell you, when you scan the bar code, exactly how much your ticket is worth.

[rcnixon]

Marginally off-topic:

That kind of thing happens with lotto-type tickets.  Clerk will run the ticket and say it's not a winner, you tell them to chuck it, and they retrieve the ticket when you leave and pocket the winnings.  Doesn't even have to be a big winning ticket.



Terry, 230RN

That's why I initial the backs of the tickets, watch them as they check and ask for the tickets back.

RUss

[RocketMan]

I wonder if the diamond testing machine is just testing for conductivity of the stone?  Diamond is carbon, and carbon is conductive.
The various types of fake stones are not conductive, SFAIK.
Could you use a DVM to test a suspect diamond?

[Tallpine]

The bigger question is how to tell a real diamond recipient from a fake 

[birdman]

I wonder if the diamond testing machine is just testing for conductivity of the stone?  Diamond is carbon, and carbon is conductive.
The various types of fake stones are not conductive, SFAIK.
Could you use a DVM to test a suspect diamond?

Actually diamond is a semiconductor, and when undoped, is an extremely good insulator (so is zircon) if you are talking electrically conductive.  If you are referring to thermal, then yes, diamond has the highest known thermal conductivity (except for CNT's and graphene, but those are visibly different).

Graphite is electrically conductive due to the ability of charge to carry across sheets as it contains mobile electrons due to its unsaturated ring structure.  The electron mobility of undoped diamond is near zero due to its fully saturated tetragonal structure
Unlike in metals where high electrical conductivity and high thermal conductivity go hand in hand (as both are due to electron mobility), in covalent crystals like diamond, thermal conductivity is due to phonons moving in the lattice--and their speed is a function of bulk modulus (stiffness).  As diamond has the highest modulus (again, excepting CNT's and graphene), it has the highest thermal conductivity (that's what the "breath test" tests, btw).

[RocketMan]

Thanks for the education, birdman.  Any speculation on how a diamond tester works, as mentioned in an earlier post?  Is it measuring electron mobility in some fashion, or would zircon and other materials make that easy to spoof?

[birdman]

Thanks for the education, birdman.  Any speculation on how a diamond tester works, as mentioned in an earlier post?  Is it measuring electron mobility in some fashion, or would zircon and other materials make that easy to spoof?

It's just measuring thermal conductivity (more accurately transient thermal diffusivuty) by seeing how much current it takes to heat a surface in contact with the stone a certain amount in a given amount of time. Not can tell real from fake, but not real from artificial.  Real from artificial depends on any contamination or doping (or micro-engraving, but that is a different aspect) yielding different flourescence.