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CVD vs HPHT

J

jenndy

Rough_Rock
Joined
Sep 23, 2010
Messages
6
Hello,
I just took in my lab diamond to a local jeweler to have it set in a necklace. I was told that my HPHT diamond is way lower quality than a CVD grown diamond. That HPHT diamonds will change color over time and are weaker. Is this true?
Thank you!
 
jenndy said:
Sell
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That's exactly why.
From what I see daily when searching for diamonds to help others out, most CVD diamonds are grainy garbage - and from what I've read by trade pros, it's likely due to poor equipment maintenance utilized in an area with a poor power infrastructure further fueled by unscrupulous growers having the desire for quantity over quality.
Clean HPHT is the closest analog to clean earth grown/natural diamond crystal, in my opinion.
High Pressure, High Temperature = the way the earth grows diamond crystal.
 
DejaWiz said:
That's exactly why.
From what I see daily when searching for diamonds to help others out, most CVD diamonds are grainy garbage - and from what I've read by trade pros, it's likely due to poor equipment maintenance utilized in an area with a poor power infrastructure further fueled by unscrupulous growers having the desire for quantity over quality.
Clean HPHT is the closest analog to clean earth grown/natural diamond crystal, in my opinion.
High Pressure, High Temperature = the way the earth grows diamond crystal.
Click to expand...

Is there a way on loosegrowndiamonds to filter to HPHT stones? I’m looking for large diamonds and they seem to be mostly CVD.
 
Lavy said:
Is there a way on loosegrowndiamonds to filter to HPHT stones? I’m looking for large diamonds and they seem to be mostly CVD.
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Yes, in the advanced filters there are toggles for HPHT and CVD...same with Ritani.
 
Yikes. I think I just bought CVD. Are they all bad? :cry:
 
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They will probably be good enough for me. Fingers crossed. Is there any way to tell from the certificate?
 
Slickk said:
No, they’re not all bad. I have two CVDs that I love and were hand picked by a trusted vendor. :)
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The IGI reports are: LG650478618 and LG652462469

You can see video on the ritani site if you enter the SKUs: SKU: D-2W8S5XNSZP and SKU: D-2W8S5WHA8Q

Ever since purchasing I've been worried! I am using them for stud earrings.
 
emmiesweetie said:
The IGI reports are: LG650478618 and LG652462469

You can see video on the ritani site if you enter the SKUs: SKU: D-2W8S5XNSZP and SKU: D-2W8S5WHA8Q

Ever since purchasing I've been worried! I am using them for stud earrings.
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You can take this link and past in the IGI cert number for a diamond and id should show a video. This is one of your stones. https://loupe360.com/diamond/652462469/ Neither looks hazy. Table sizes are 1% different. I still run everything through the HCA cut adviser.
 
Here's the other one.

Loupe360

loupe360.com loupe360.com

They look great! You did great! Please post photos once you get them in hand. We love photos!
 
Oh, thank you so much! That is so reassuring! I will post when the stones arrive. Then I'm going to bring them to my jeweler and talk about Settings. I probably won't have the finished product in hand for a little while because technically this is a birthday present from my hubby. And my birthday is in April. Lucky me to have such a birthstone!
 
0515vision said:
Here's the other one.

Loupe360

loupe360.com loupe360.com

They look great! You did great! Please post photos once you get them in hand. We love photos!
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Add /video to the end of the URL to see the full size video ... although the resolution is still pretty poor, I can definitely see some CVD graining throughout the diamond as I rotate the video slowly.
Here's a screenshot:

Screenshot_20250202-094841-324.png
 
Interesting! Tell me more about what that means in terms of appearance for the studs. Like, to the naked eye!
 
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emmiesweetie said:
Interesting! Tell me more about what that means in terms of appearance for the studs. Like, to the naked eye!
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If you decide to move forward with those diamonds, then please be sure to assess them in a variety of different lighting conditions to make sure there are no transparency issues.
Here's a great write-up by Bryan Boyne of Whiteflash regarding all that:

Texas Leaguer

Thread 'Milky Diamonds – What Causes Transparency Issues and How to Identify Them'

We tend to think of diamond as a totally transparent material but that is not always the case. Sometimes diamonds are hazy and often described as looking “milky”. Diamonds can appear milky for a number of reasons. Most often the cause is related to the presence of clarity characteristics such as microscopic inclusions, but can also be the result of defects at the atomic level in the carbon lattice. Strong fluorescence, particularly in combination with light scattering inclusions, can also cause a loss of transparency resulting in the diamond having a hazy or milky appearance.

It should be...
  • Like
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Given that these are both around .49 ct and for studs, don't you think the graining is minimal, @DejaWiz?

If this were a 2 ct stone for an e-ring, I'd be concerned. But the cut precision is great, and these will be seen from relatively far away (as compared to a ring which is held up to your face quite often).
 
0515vision said:
Given that these are both around .49 ct and for studs, don't you think the graining is minimal, @DejaWiz?

If this were a 2 ct stone for an e-ring, I'd be concerned. But the cut precision is great, and these will be seen from relatively far away (as compared to a ring which is held up to your face quite often).
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Graining can cause light scattering no matter the carat size, yes?
My thoughts are that it is something that needs to be checked for, unless the intent is to purposely want milky/subdued diamonds for earrings.
 
DejaWiz said:
Graining can cause light scattering no matter the carat size, yes?
My thoughts are that it is something that needs to be checked for, unless the intent is to purposely want milky/subdued diamonds for earrings.
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OK this is interesting. Technically they haven't shipped yet because my return to them is still en route. They've been set aside as sold, however.

My goal is not to have milky diamonds, no. My goal is to stay in budget though. These two stones seemed good for the money, but I'm open to other suggestions! My other goal is to have a nice pair of earrings in hand (or ear, as it were!) by my birthday month, April, so I have a little bit of time. Total budget would be a little bit over 600 and I've spoken to my jeweler who will be able to set them in platinum (due to allergy issues) for around 200. Like I said earlier in the thread, I paid a little bit over 200 for each stone.

And while it's true that I of course want the nicest stones for my money, I am pretty new to all of this and probably don't have the same kind of discerning eye as many other folks on the forum. But, I wouldn't mind something that knocks my socks off, obviously!

My engagement ring, for reference is a 1940s old European cut, .75 ct center stone with eight tiny diamonds flanking. Color is G and clarity is VS. That's pretty much all I know about it and I really love it and never tired of seeing it on my finger, even after 20+ years. Don't know what it looks like under a loop and probably don't care! When we bought it we just thought it looked pretty and neither of us knew anything about diamonds we just knew we wanted something vintage. To be honest I haven't thought about another diamond purchase until now. It's been a really interesting education – I can see why people are so into it! I'm learning a lot.

What do you think? Do you think I could get more for my money?
 
@emmiesweetie I'm jumping over to your own thread as to not hijack this one.
 
My understanding is that CVD diamonds simply require more scrupulous screening (particularly using polarizer filters to assess graining), but *can* look every bit as good as HPHT diamonds if well-chosen. Am I understanding this correctly?

Some of the higher-end sellers like DistinctiveGem seem to pride themselves on their screening protocols.
 
Dr_Diesel said:
My understanding is that CVD diamonds simply require more scrupulous screening (particularly using polarizer filters to assess graining), but *can* look every bit as good as HPHT diamonds if well-chosen. Am I understanding this correctly?

Some of the higher-end sellers like DistinctiveGem seem to pride themselves on their screening protocols.
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100% correct, Dr_Diesel!
 
Just a fly-by polarizing filters check for strain not graining
 
Karl_K said:
Just a fly-by polarizing filters check for strain not graining
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Thank you for clarifying that it is for checking strain vs grain, Karl.
 
emmiesweetie said:
Yikes. I think I just bought CVD. Are they all bad? :cry:
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I prefer CVD for the price and inventory, we like what we like, lol
I agree that you just need to really look at it carefully
 
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Dr_Diesel said:
@Karl_K So how do you check for grain? Darkfield?
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Darkfield will hide it.
Loupe or microscope.
Check at angles + face up.

Video you can control the tilt on can also show it.
 
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