Two main methods are used. High Pressure High Temperature and Chemical Vapor Deposition. Both produce diamonds that can be cut and polished like mined stones. Once finished they are graded using the same basic criteria you already know. Cut color clarity and carat weight.
Because these diamonds are made above ground they offer a more predictable supply. This affects price and availability. It also makes grading reports even more important since many stones can look similar at first glance.
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Why grading matters more for lab made diamonds
When you buy a lab made diamonds you rely heavily on the grading report. You cannot see atomic structure. You judge quality based on documented measurements. Small differences in color or clarity can change value in a way that is not obvious to the eye.
A grading report answers key questions.
- Is the diamond truly lab grown
- How consistent is the color grade
- Are clarity features mapped clearly
- Is the cut measured with precision
Without a trusted report you are guessing. With one you can compare stones across sellers and prices.
The role of IGI and GIA in lab grown grading
IGI and GIA are the two most common laboratories grading lab grown diamonds. They do the same core task but they do not approach it in the same way.
GIA built its reputation on natural diamond grading. It introduced lab grown reports later and applies strict internal controls. IGI adopted lab grown grading earlier and handles a higher volume of these stones.
This difference shapes how each report reads and how the market responds to it.
GIA grading approach
GIA focuses on consistency and conservative grading. Color and clarity grades tend to be tighter. This can mean a diamond graded by GIA may appear similar to a higher grade stone from another lab.
GIA reports are detailed but restrained. They avoid extra labels and focus on core data. For buyers who want alignment with natural diamond standards this approach feels familiar.
IGI grading approach
IGI grades a large share of lab grown diamonds sold today. Their reports are easy to read and widely accepted in retail settings. Color and clarity grades may appear slightly more generous in some cases.
IGI also includes more production details. For many buyers this added context helps them understand how the diamond was created and finished.
How this affects your buying decision
The comparison igi vs gia lab grown exists because grading affects price perception. A diamond with the same physical qualities may be priced differently depending on the report.
Here is how to think about it in practical terms.
If you want tighter grading and long term consistency
You may lean toward GIA. This is useful if you plan to compare lab grown and mined diamonds side by side.
If you want broader selection and easier comparison within lab grown stones
You may find IGI more practical. Most lab grown inventory is already graded by IGI.
Example
You compare two lab made diamonds online. Both list the same carat weight and clarity. One has a GIA report and costs more. The other has an IGI report and costs less. The price gap reflects grading perception not just the stone itself.
Pricing and resale reality
Lab made diamonds do not follow the same resale patterns as mined diamonds. Certification still matters but in a different way. The report helps establish trust at the time of purchase. It does not guarantee future value.
In the igi vs gia lab grown discussion resale often comes up. In practice most resale buyers focus on physical quality and current market demand. The lab name matters less than initial accuracy and transparency.
How to read a lab grown diamond report
Do not stop at the headline grades. Look deeper.
Check the cut measurements. Table depth and angles influence how the diamond handles light.
Review clarity maps. Identify where inclusions sit and whether they affect durability or appearance.
Confirm growth method disclosure. This helps you understand potential color tints or strain patterns.
Ask for images or videos. Reports support visuals. They do not replace them.
Choosing with confidence
The real choice is not IGI or GIA in isolation. It is whether the report gives you enough reliable information to decide.
Use igi vs gia lab grown as a framework not a rule. Compare stones on equal terms. Focus on what you can verify. Pay for quality you can see and document.
FAQ
Are lab made diamonds lower quality than mined ones
No. Quality depends on how the diamond is grown and cut. Origin does not determine performance or durability.
Does a GIA report always mean a better lab grown diamond
No. It means the grading is conservative. The diamond itself may be similar to an IGI graded stone with the same measurements.
Should I avoid IGI graded lab grown diamonds
No. IGI graded stones make up most of the lab grown market. The key is to read the report carefully and compare real data not labels alone.