Buying a diamond was filled in the not so distant past with a couple of easy questions What is the weight of the carat, exactly? How good is the cut? What are the color and clarity standards of the diamond? And there is yet another fact worth mentioning on lab grown diamonds HPHT
HPHT stands for high pressure, high temperature. There are two common processes in producing the gem quality lab diamonds HPHT and chemical vapour deposition (CVD). An HPHT stone is not cubic zirconia, moissanite, or another diamond look-alike. Laboratory-grown diamonds have essentially the same chemical composition and crystal structure of natural diamonds, according to the Gemological Institute of America (GIA).
That’s good news for people shopping in the engagement rings Singapore, loose diamonds, or other fine jewellery.
What Are Lab Grown Diamonds HPHT?
An HPHT diamond starts with a seed rather than a full-form finished stone. The seed is placed in special equipment with access to a carbon source and with a metallic flux or catalyst.
In the growth chamber, the conditions are extreme. GIA notes common pressures of approximately 5-6 GPa and temperatures of about 1,300-1,600°C in the HPHT process. Carbon goes into solution in the metallic material and then crystallises on a cooler diamond seed. The crystal grows until there is enough to cut and polish a finished gemstone.
It’s an accelerated reproduction of certain key conditions under which natural diamonds form. The difference is that this happens in a controlled setting, not kilometres underground.
The resulting crystal still needs the process steps familiar to people shopping for finished diamonds – planning, cutting and polishing. After all, it’s not as though a grown crystal will magically appear in the desired shape.
HPHT Is a Growth Method, Not a Diamond Grade
This fact bears particular importance for those who review product information.
“HPHT” simply identifies how a laboratory-grown diamond was produced. The process does not identify whether the resulting diamond has an excellent cut, high clarity, desirable color or pleasing proportions.
Two HPHT diamonds of the same carat weight might look very different, depending on their individual cut quality, color, clarity and proportions. Buyers in Singapore and elsewhere should ensure they are not looking past individual characteristics of a diamond to make an assumption about its appearance based on the production method.
Lab Grown Diamonds HPHT vs CVD
CVD, or chemical vapour decomposition, is a growth method that creates diamonds in a different environment. Diamond seed plates are placed into a chamber containing carbon gas (this is usually methane and hydrogen). The energy activates the gasses. Carbon bonds to the substrate of the diamond plates and the crystal grows.
Diamonds grown this way do not use the same pressure or heat as HPHT. GIA points out that a substantial amount of diamonds examined in their laboratory are grown using the CVD method.
There is also a caveat to this comparison in how HPHT vs CVD diamonds are sold – a CVD-grown diamond crystal might be treated with HPHT after the growth process is complete.
HPHT Treatment After CVD Growth
HPHT treatment after the growth can also modify undesired hues in some CVD-treated material – though that does not categorize it as an HPHT-grown diamond. The crystal still has a CVD growth method, with HPHT post-growth processing – and GIA says that’s increasingly common for CVD diamonds submitted for examination.
That’s why a reliable laboratory report is more valuable than a brief product description.
Are HPHT Lab Diamonds Real Diamonds?
Yes – scientifically speaking, these are diamonds, with the same chemical composition and crystalline structure as natural diamonds.
GIA points out that diamonds grown in a lab have the same crystal structure and chemical composition as natural diamonds, and appear the same to the unaided eye. They only differ in terms of origin.
This is also part of the reason why it could be misleading to refer to a lab-grown diamond as “fake”. Materials such as cubic zirconia or moissanite would qualify as simulants – but a diamond, grown in a lab, is still a diamond. The origin should be readily apparent if the diamond is properly disclosed.
What Can Be Different Inside an HPHT Diamond?
The differences between naturally-grown, HPHT-grown, or CVD-grown diamonds could be subtle enough that identification requires gemological inspection.
HPHT crystal formations sometimes contain unique formation features (growth structures), fluorescence behavior or colour zoning, or metallic flux inclusions related to the growth process. That does not mean someone should try to identify a diamond based on an online examination. With advances in technology, it has affected lab-grown diamond creation in a similar way: HPHT material was historically prone to show stronger colours, while the modern ability to grow high quality colourless or near-colourless HPHT stones is much larger.
Why the Cut Matters in an HPHT Diamond
What makes the cut (or lack thereof) so important in a diamond. In most cases, a diamond with poor proportional characteristics will never become a beautiful stone simply because it was HPHT-grown.
When comparison shopping, make note of a lab diamond’s cut grade (when applicable), dimensions, and proportions, as well as the colour and clarity. For certain fancy shapes (ovals, pears, emeralds, radiants, cushions), photographs and video content can also help, as two seemingly equal stones might have vastly differing appearance when mounted.
The real question is not, “Is HPHT good?” but rather, “is this diamond good?”
Read the Laboratory Report Before Buying
Independent documentation becomes that much more valuable when it comes to laboratory-grown stones – as the GIA highlights, origin is not always easily identifiable through regular inspection. The GIA’s laboratory-grown reports identify if the stone is either HPHT- or CVD-grown, and provide information about any relevant post-growth treatment.
Before purchasing a loose diamond or engagement ring, double-check that the information on the report and the carat weight, size, colour, clarity and growth data matches up with the stone being offered for sale.
A grading report is not the same thing as an appraisal, as its purpose is to identify the gemological features of a diamond.
Choosing an HPHT Diamond in Singapore
Singapore shoppers are fortunate enough that the ability to review stones online makes it easier to plan on what to look for before visiting a jeweler in person. With that said, the greater accessibility to information also means it is easy to get distracted and pay more attention to a stone’s feature list than it actually impacts on the appearance.
Start with an initial budget and shape, and compare the cut and size (within a similar range), proportions, colour and clarity, and if applicable, examine the photographs and videos. It might also useful to peruse other retailers offering lab-grown diamonds in the context of the broader Singapore market. NOVITA DIAMONDS, as a resource, offers Singapore shoppers a dedicated selection of lab-grown diamond jewelry and loose stones – an option to consider when comparison shopping.
While it is necessary to know about the retailer, as much attention should be paid to the diamond itself: its origin, characteristics and appearance.
Should You Choose HPHT or CVD?
There is no particular law that says that anyone shopping for lab-grown diamonds in Singapore (or anywhere, for that matter) should choose one technology over another.
They both have the capacity to produce gem-quality diamonds with varying levels of quality.
One poorly-cut HPHT stone will not look any better than a badly-cut CVD diamond. At the same time, an attractively-cut HPHT might appeal more to one buyer than another CVD stone. The choice is personal – but it need not be based on any particular ideology about the technology itself.
What to Check Before Choosing Lab Grown Diamond HPHT
A buyer looking for lab grown diamonds hpht should keep it simple: the most important things are to make sure it is actually HPHT-grown, read the laboratory documentation carefully, and examine the appearance of the finished diamond against its characteristics as a whole, rather than focusing on the production method itself.