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Color change in diamonds?

monipod

Brilliant_Rock
Joined
Jun 25, 2019
Messages
668
I think it's usually done to brown-tinted stones. It's considered a treated stone so the price should reflect that if you're buying.
 

Rockcollector

Shiny_Rock
Joined
Jan 11, 2019
Messages
221
No. Just saw a 3 carat diamond on EBay for 19k and wondered what the cert looked like!
 

nojs

Shiny_Rock
Joined
Nov 22, 2014
Messages
217
Does anyone know where to buy HPHT mined diamonds? White, around 1-1.5 ct. I’d be interested :)
 

oldminer

Ideal_Rock
Trade
Joined
Sep 3, 2000
Messages
6,503
Keep in mind that these once brown diamonds, now close to colorless but treated by HPHT, have little market demand. Nearly every dealer will refuse to buy them. Buying one of these properly would take a lot of effort to get to a price that could be justified, as they have nearly no residual value. While there is not much reason for this prejudice against them within the trade, this prejudice is not well understood by potential retail consumers. Being aware of this might help to properly balance your desire to buy what initially may appear to be a bargain unless you know about their very weak market that does does not support the usual asking prices. You have to research before making even what you think is a "low" offer. It might still be way too high, in some instances. Caution is called for.
 

Rockdiamond

Ideal_Rock
Trade
Joined
Jan 7, 2009
Messages
8,476
Personally, I'd never touch an HPHT stone- but that has a lot to do with our reputation for carrying natural Fancy Colored diamonds.
Still- advising a consumer on this...my prejudices do matter- because as my friend David points out- dealers won't buy such a stone.
If you really love the stone, I'd look into what a lab-grown stone of similar size would cost...and base evaluation on that.
 

nojs

Shiny_Rock
Joined
Nov 22, 2014
Messages
217
Keep in mind that these once brown diamonds, now close to colorless but treated by HPHT, have little market demand. Nearly every dealer will refuse to buy them. Buying one of these properly would take a lot of effort to get to a price that could be justified, as they have nearly no residual value. While there is not much reason for this prejudice against them within the trade, this prejudice is not well understood by potential retail consumers. Being aware of this might help to properly balance your desire to buy what initially may appear to be a bargain unless you know about their very weak market that does does not support the usual asking prices. You have to research before making even what you think is a "low" offer. It might still be way too high, in some instances. Caution is called for.

I don’t know about OP, but I certainly am buying for my own pleasure with no intent ever selling the stones. And I’m only willing to pay very little :)
 

Rockdiamond

Ideal_Rock
Trade
Joined
Jan 7, 2009
Messages
8,476
Why is it so bad to buy them?

It's by no means "bad" to buy HPHT, or lab grown- it's a matter of personal choice.
What I stress is that if one is making that choice, to make sure the price is commensurate.
The fact that dealers won't buy such stones on the secondary market absolutely impacts the value at purchase time for a consumer.
 

oldminer

Ideal_Rock
Trade
Joined
Sep 3, 2000
Messages
6,503
Several years ago, I had a good friend, a long time diamond dealer in Philly, who bought a 7ct E-VVS1 pear shape knowing it was HPHT enhanced. He paid next to nothing for it. Less than 20% of the 5 carat Rap sheet price. He was a taking a chance, but thought "How could it be worth less?" After owning it for more than 5 years he came around to the understanding that he could only retail the stone as there just was no dealer who liked it as much as he once did.

I believe he eventually sold it for just about what he paid to a consumer who felt that they wanted to pay next to nothing, or as little as possible, for a fantastically beautiful and well cut diamond. I found it very difficult to believe he was not able to sell it for a profit. There was nothing at all wrong with the diamond or the way it looked. It is all about some the inherent traditional conservatism of the diamond trade. Whether this is a justified conservatism or not, it is the way it has been for a decades. This is not a new treatment. Personally, I think there are beautiful and very inexpensive diamonds of this sort floating around worthy of consideration. Bought very inexpensively, they are not a bad deal. You don't want to overpay and to get to the right price, you must be well informed.
 

foxinsox

Ideal_Rock
Premium
Joined
Jul 18, 2015
Messages
3,362
Is HPHT a permanent treatment? I would absolutely love to find a large old cut that was ridiculously affordable this way! Mind you, I would also like a light brown tinted old cut so I might prefer the before colour...
 

oldminer

Ideal_Rock
Trade
Joined
Sep 3, 2000
Messages
6,503
It is a permanent treatment, but only for brown tint type IIA diamonds. There are not a lot of these diamonds around to be treated. It is a rare type of natural diamond. All the colorless man-made diamonds happen to be type IIA, too. The science behind all of this is amazingly complex. Then, too, the HTHP treatment requires a rather high clarity diamond since included diamonds can readily break up with the heat and pressure. You probably wouldn't want to take the risks that diamond merchants might accept as part of their business model.
 

monipod

Brilliant_Rock
Joined
Jun 25, 2019
Messages
668
Does anyone know where to buy HPHT mined diamonds? White, around 1-1.5 ct. I’d be interested :)

I see a lot of sellers on ebay with listings for natural but colour and/or clarity enhanced stones. US vendor/s but I can't remember usernames. Usually they openly say 'treated' in the item title.
 

Texas Leaguer

Ideal_Rock
Trade
Joined
Jul 27, 2009
Messages
3,338
I agree with @oldminer and @Rockdiamond that there is nothing inherently wrong with buying a treated or synthetic diamond. They are just cautioning that it is difficult if not impossible to determine an accurate value for such things.

Lab grown diamonds have minimal and diminishing resale value as more and bigger synthetics continue to come into the market at ever lower prices. This is the expected product cycle of a synthetic gemstone and there are many historical examples that have followed this trajectory.

In a sense, an Earth mined diamond that has undergone a permanent color enhancement should be more valuable than a synthetic. But the market is not always logical. Some traits cause the market to behave irrationally. And as a consumer it pays to be aware of market quirks.
 

Rockdiamond

Ideal_Rock
Trade
Joined
Jan 7, 2009
Messages
8,476
But the market is not always logical.
What a great point!!
As an example: Brown diamonds, which can be quite lovely, are valued at a fraction of yellow. Yellow, which is also pretty is a fraction of pink.
Rarity definitely plays a role in the prices....but its not linear...that is to say, prices are not based on rarity alone
 
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