How to Differentiate HPHT And CVD Lab Grown Diamonds?

Comparing CVD and HPHT Lab-Grown Diamonds

Everyone’s not only talking about lab-grown diamonds, but most conscious consumers are opting to buy lab diamonds as opposed to mined diamonds.

Lab cultured diamonds are made through two techniques: high pressure high temperature (HPHT) and chemical vapor deposition (CVD). In this blog, we’ll focus on learning more about these two methods and how you can identify one diamond from the other.

Let’s get started!

Methods to manufacture lab grown diamonds

Laboratory diamonds are made with two methods. Let’s explore both the methods in detail:

HPHT Method

In the HPHT method of creating diamonds, diamond seeds are put into a sealed vacuum chamber and put through high temperature and high pressure. This leads to chemical reactions with the diamond seed and forms a rough diamond crystal.

The temperature and pressure mimic the intensity that forms diamonds under the surface of the earth. The temperature ranges between 1300 to 1600°C. The pressure is equal to 8,70,000 pounds per square inch. Once the diamonds are formed, they are sent for cutting and polishing.

CVD Method

In the CVD method of creating diamonds, diamond seeds or diamond crystals are put into a sealed vacuum chamber. Then carbon gases are introduced into this chamber. The chemical reactions create deposits on the seed, forming the rough diamond.

The CVD method takes about two to four weeks to create diamonds. Once the process is over, the rough CVD diamonds have to go through the process of cutting and polishing. The time required for CVD diamonds to form also depends on the quality of the diamond seed, the size of the chamber, and the number of seeds in a chamber.

Differentiating CVD and HPHT diamonds

Even though CVD and HPHT diamonds are made with the same processes that form diamonds under the Earth, there is a difference in properties of both these types of diamonds.

Gemologists and diamond experts can differentiate between the two types of diamonds with the help of special equipment and skills. For instance, they assess the color distribution, pattern of grains, fluorescence color, inclusions, and the inscription on the girdle made by the lab grown diamond manufacturing company.

Here’s a table that shows how you can differentiate between HPHT and CVD diamonds.

Properties	HPHT	CVD
Color distribution	HPHT diamonds display inconsistency in color in the overall diamond. This is due to the process that produces this lab diamond. When nitrogen is unevenly distributed the lab grown diamond gets an uneven color.	CVD diamonds have a more even color distribution than HPHT diamonds. That is because the gasses hydrogen and methane spread evenly during the process of the lab diamond formation.
Graining in the diamond	HPHT diamonds have grains in them. Due to the production process, this type of diamond has a graining pattern inside it.	CVD diamonds do not have any graining pattern because of the internal growth composition during the process.
Fluorescence	Lab cultured diamonds made through HPHT process, display fluorescence color on their crown or pavilion.	Diamonds grown in labs through the CVD process may or may not display fluorescence color.
Inclusions	Lab grown diamonds made via HPHT have dark or opaque inclusions. However, they exhibit a metallic shine under the light. The metals and chemical reactions during the process of production merge with the diamond seed and become inclusions.	CVD diamonds also have inclusions. However, their inclusions are based on the minerals part of their composition. The nature of inclusions in CVD lab produced diamonds is different
Inscription on girdle	Diamonds grown in labs have an inscription on the girdle. This inscription mentions the process through which the diamond is made.	Lab produced diamonds made through CVD process have an inscription on the girdle that mentions the diamond process.

Summing up

When it comes to identifying diamonds, whether mined or lab grown diamonds, or HPHT or CVD diamonds, there are a lot of factors that must be considered. Diamond experts follow standard methods created by diamond institutions. However, differentiating diamonds also requires special equipment.

The above-mentioned details will help you understand the difference between HPHT and CVD diamonds and also ensure you buy lab grown diamonds more confidently, the next time around!

{"AutoID":143,"DateCreation":"\/Date(1716553067190)\/","DateModified":"\/Date(1719475172167)\/","CreatedBy":null,"ModifiedBy":"Rahul Bohra ","RecordStatus":"A","Title":"How to Differentiate HPHT And CVD Lab Grown Diamonds?","SubTitle":null,"Description":"\u003cp dir=\"ltr\"\u003eEveryone\u0026rsquo;s not only talking about lab-grown diamonds, but most conscious consumers are opting to buy lab diamonds as opposed to mined diamonds.\u0026nbsp;\u003c/p\u003e\r\n\r\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\r\n\r\n\u003cp dir=\"ltr\"\u003e\u003ca href=\"https://www.growndiamondcorp.com/blog/types-of-lab-grown-diamonds/\"\u003eLab cultured diamonds\u003c/a\u003e are made through two techniques: high pressure high temperature (HPHT) and chemical vapor deposition (CVD). In this blog, we\u0026rsquo;ll focus on learning more about these two methods and how you can identify one diamond from the other.\u003c/p\u003e\r\n\r\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\r\n\r\n\u003cp dir=\"ltr\"\u003eLet\u0026rsquo;s get started!\u003c/p\u003e\r\n\r\n\u003cp dir=\"ltr\"\u003e\u0026nbsp;\u003c/p\u003e\r\n\r\n\u003ch2 dir=\"ltr\"\u003e\u003cstrong\u003eMethods to manufacture lab grown diamonds\u003c/strong\u003e\u003c/h2\u003e\r\n\r\n\u003cp dir=\"ltr\"\u003eLaboratory diamonds are made with two methods. Let\u0026rsquo;s explore both the methods in detail:\u003c/p\u003e\r\n\r\n\u003ch3 dir=\"ltr\"\u003e\u003cstrong\u003eHPHT Method\u003c/strong\u003e\u003c/h3\u003e\r\n\r\n\u003cp dir=\"ltr\"\u003eIn the HPHT method of creating diamonds, diamond seeds are put into a sealed vacuum chamber and put through high temperature and high pressure. This leads to chemical reactions with the diamond seed and forms a rough diamond crystal.\u0026nbsp;\u003c/p\u003e\r\n\r\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\r\n\r\n\u003cp dir=\"ltr\"\u003eThe temperature and pressure mimic the intensity that forms diamonds under the surface of the earth. The temperature ranges between 1300 to 1600\u0026deg;C. The pressure is equal to 8,70,000 pounds per square inch. Once the diamonds are formed, they are sent for cutting and polishing.\u003c/p\u003e\r\n\r\n\u003cp dir=\"ltr\"\u003e\u0026nbsp;\u003c/p\u003e\r\n\r\n\u003ch3 dir=\"ltr\"\u003e\u003cstrong\u003eCVD Method\u003c/strong\u003e\u003c/h3\u003e\r\n\r\n\u003cp dir=\"ltr\"\u003eIn the CVD method of creating diamonds, diamond seeds or diamond crystals are put into a sealed vacuum chamber. Then carbon gases are introduced into this chamber. The chemical reactions create deposits on the seed, forming the rough diamond.\u0026nbsp;\u003c/p\u003e\r\n\r\n\u003cp dir=\"ltr\"\u003e\u003cbr /\u003e\r\nThe CVD method takes about two to four weeks to create diamonds. Once the process is over, the rough \u003ca href=\"https://www.growndiamondcorp.com/blog/cvd-diamonds-everything-you-need-to-know/\"\u003eCVD diamonds\u003c/a\u003e have to go through the process of cutting and polishing. The time required for CVD diamonds to form also depends on the quality of the diamond seed, the size of the chamber, and the number of seeds in a chamber.\u003c/p\u003e\r\n\r\n\u003cp dir=\"ltr\"\u003e\u0026nbsp;\u003c/p\u003e\r\n\r\n\u003cp dir=\"ltr\"\u003e\u0026nbsp;\u003c/p\u003e\r\n\r\n\u003ch2 dir=\"ltr\"\u003e\u003cstrong\u003eDifferentiating CVD and HPHT diamonds\u003c/strong\u003e\u003c/h2\u003e\r\n\r\n\u003cp dir=\"ltr\"\u003eEven though CVD and \u003ca href=\"https://www.growndiamondcorp.com/blog/hpht-lab-grown-diamonds-history-process-and-benefits/\"\u003eHPHT diamonds\u003c/a\u003e are made with the same processes that form diamonds under the Earth, there is a difference in properties of both these types of diamonds.\u0026nbsp;\u003c/p\u003e\r\n\r\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\r\n\r\n\u003cp dir=\"ltr\"\u003eGemologists and diamond experts can differentiate between the two types of diamonds with the help of special equipment and skills. For instance, they assess the color distribution, pattern of grains, fluorescence color, inclusions, and the inscription on the girdle made by the lab grown diamond manufacturing company.\u003c/p\u003e\r\n\r\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\r\n\r\n\u003cp dir=\"ltr\"\u003eHere\u0026rsquo;s a table that shows how you can differentiate between HPHT and CVD diamonds.\u003c/p\u003e\r\n\r\n\u003cp dir=\"ltr\"\u003e\u0026nbsp;\u003c/p\u003e\r\n\r\n\u003ctable border=\"1\" cellpadding=\"1\" cellspacing=\"1\" style=\"width:800px\"\u003e\r\n\t\u003ctbody\u003e\r\n\t\t\u003ctr\u003e\r\n\t\t\t\u003ctd\u003e\u003cstrong\u003eProperties\u003c/strong\u003e\u003c/td\u003e\r\n\t\t\t\u003ctd\u003e\u003cstrong\u003eHPHT\u003c/strong\u003e\u003c/td\u003e\r\n\t\t\t\u003ctd\u003e\u003cstrong\u003eCVD\u003c/strong\u003e\u003c/td\u003e\r\n\t\t\u003c/tr\u003e\r\n\t\t\u003ctr\u003e\r\n\t\t\t\u003ctd\u003eColor distribution\u003c/td\u003e\r\n\t\t\t\u003ctd\u003eHPHT diamonds display inconsistency in color in the overall diamond. This is due to the process that produces this \u003ca href=\"https://www.growndiamondcorp.com/blog/types-of-lab-grown-diamonds/\"\u003elab diamond\u003c/a\u003e. When nitrogen is unevenly distributed the lab grown diamond gets an uneven color.\u003c/td\u003e\r\n\t\t\t\u003ctd\u003eCVD diamonds have a more even color distribution than HPHT diamonds. That is because the gasses hydrogen and methane spread evenly during the process of the lab diamond formation.\u003c/td\u003e\r\n\t\t\u003c/tr\u003e\r\n\t\t\u003ctr\u003e\r\n\t\t\t\u003ctd\u003eGraining in the diamond\u003c/td\u003e\r\n\t\t\t\u003ctd\u003eHPHT diamonds have grains in them. Due to the production process, this type of diamond has a graining pattern inside it.\u003c/td\u003e\r\n\t\t\t\u003ctd\u003eCVD diamonds do not have any graining pattern because of the internal growth composition during the process.\u003c/td\u003e\r\n\t\t\u003c/tr\u003e\r\n\t\t\u003ctr\u003e\r\n\t\t\t\u003ctd\u003eFluorescence\u003c/td\u003e\r\n\t\t\t\u003ctd\u003eLab cultured diamonds made through HPHT process, display fluorescence color on their crown or pavilion.\u003c/td\u003e\r\n\t\t\t\u003ctd\u003e\u003ca href=\"https://www.growndiamondcorp.com/\"\u003eDiamonds grown in labs\u003c/a\u003e through the CVD process may or may not display fluorescence color.\u003c/td\u003e\r\n\t\t\u003c/tr\u003e\r\n\t\t\u003ctr\u003e\r\n\t\t\t\u003ctd\u003eInclusions\u003c/td\u003e\r\n\t\t\t\u003ctd\u003e\u003ca href=\"https://www.growndiamondcorp.com/\"\u003eLab grown diamonds\u003c/a\u003e made via HPHT have dark or opaque inclusions. However, they exhibit a metallic shine under the light. The metals and chemical reactions during the process of production merge with the diamond seed and become inclusions.\u003c/td\u003e\r\n\t\t\t\u003ctd\u003eCVD diamonds also have inclusions. However, their inclusions are based on the minerals part of their composition. The nature of inclusions in CVD lab produced diamonds is different\u003c/td\u003e\r\n\t\t\u003c/tr\u003e\r\n\t\t\u003ctr\u003e\r\n\t\t\t\u003ctd\u003eInscription on girdle\u003c/td\u003e\r\n\t\t\t\u003ctd\u003eDiamonds grown in labs have an inscription on the girdle. This inscription mentions the process through which the diamond is made.\u003c/td\u003e\r\n\t\t\t\u003ctd\u003e\u003ca href=\"https://www.growndiamondcorp.com/blog/types-of-lab-grown-diamonds/\"\u003eLab produced diamonds\u003c/a\u003e made through CVD process have an inscription on the girdle that mentions the diamond process.\u003c/td\u003e\r\n\t\t\u003c/tr\u003e\r\n\t\u003c/tbody\u003e\r\n\u003c/table\u003e\r\n\r\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\r\n\r\n\u003ch2\u003e\u003cstrong\u003eSumming up\u003c/strong\u003e\u003c/h2\u003e\r\n\r\n\u003cp dir=\"ltr\"\u003eWhen it comes to identifying diamonds, whether mined or lab grown diamonds, or HPHT or CVD diamonds, there are a lot of factors that must be considered. Diamond experts follow standard methods created by diamond institutions. However, differentiating diamonds also requires special equipment.\u0026nbsp;\u003c/p\u003e\r\n\r\n\u003cp\u003e\u003cbr /\u003e\r\nThe above-mentioned details will help you understand the difference between HPHT and CVD diamonds and also ensure you \u003ca href=\"https://www.growndiamondcorp.com/\"\u003ebuy lab grown diamonds\u003c/a\u003e more confidently, the next time around!\u003c/p\u003e\r\n","FromDate":null,"ToDate":null,"Image_Url":"how-to-differentiate-hpht-and-cvd-lab-grown-diamonds.png","Image_Alt":"Comparing CVD and HPHT Lab-Grown Diamonds","KeyWords":"lab grown diamonds, Diamonds grown in Lab, Lab cultured diamond, Lab produced diamonds, lab diamond, cvd diamond, hpht diamond","MetaDescription":"Here you can learn the difference between HPHT and CVD lab-grown diamonds, along with their unique properties, production methods, and identification techniques for these ethical diamond alternatives.","MetaTitle":"How to Differentiate HPHT And CVD Lab Grown Diamonds?","CanonicalLink":null,"MetaContent":"\u003c!-- Open Graph / Facebook --\u003e\r\n\u003cmeta property=\"og:type\" content=\"website\"\u003e\r\n\u003cmeta property=\"og:url\" content =\"https://www.growndiamondcorp.com/blog/how-to-differentiate-hpht-and-cvd-lab-grown-diamonds/\"\u003e\r\n\u003cmeta property=\"og:title\" content=\"How to Differentiate HPHT And CVD Lab Grown Diamonds? | Grown Diamond Corporation\"\u003e\r\n\u003cmeta property=\"og:description\" content=\"Here you can learn the difference between HPHT and CVD lab-grown diamonds, along with their unique properties, production methods, and identification techniques for these ethical diamond alternatives.\"\u003e\r\n\u003cmeta property=\"og:image\" content=\"https://docs.growndiamondcorp.com/blog/how-to-differentiate-hpht-and-cvd-lab-grown-diamonds.png\"\u003e\r\n\r\n\u003c!-- Twitter --\u003e\r\n\u003cmeta property=\"twitter:card\" content=\"summary_large_image\"\u003e\r\n\u003cmeta property=\"twitter:url\" content=\"https://www.growndiamondcorp.com/blog/how-to-differentiate-hpht-and-cvd-lab-grown-diamonds/\"\u003e\r\n\u003cmeta property=\"twitter:title\" content=\"How to Differentiate HPHT And CVD Lab Grown Diamonds? | Grown Diamond Corporation\"\u003e\r\n\u003cmeta property=\"twitter:description\" content=\"Here you can learn the difference between HPHT and CVD lab-grown diamonds, along with their unique properties, production methods, and identification techniques for these ethical diamond alternatives.\"\u003e\r\n\u003cmeta property=\"twitter:image\" content=\"https://docs.growndiamondcorp.com/blog/how-to-differentiate-hpht-and-cvd-lab-grown-diamonds.png\"\u003e","SeqNo":null,"Slug":"how-to-differentiate-hpht-and-cvd-lab-grown-diamonds","GetTitle":"how-to-differentiate-hpht-and-cvd-lab-grown-diamonds","GetImageUrl":"https://docs.growndiamondcorp.com/blog/how-to-differentiate-hpht-and-cvd-lab-grown-diamonds.png"}