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A Guide To Lab Grown Diamonds

An Overview

Natural diamonds have long fascinated mankind
with their unique physical and visual properties.
Features such as exceptional hardness, durability,
light reflectivity (brilliance) and dispersion (fire)
distinguish them from other gems. The beauty and
universal appeal of natural diamonds come at a
price, as the recovery and fashioning of such rare
gems are challenging.
For decades, researchers have sought to create
diamonds in laboratories. Research began in the early
1900s, but success in synthesizing diamonds did not
occur until the mid-1950s. Gem-quality laboratorygrown
diamonds, also known as man-made diamonds,
took another couple of decades to perfect, however the
growth rate was slow and the cost was high.
A rapid increase in laboratory-grown
diamond growth technology over the past
decade has added to their availability in
the jewelry market as an alternative to
natural diamonds.
GIA has followed the developments of laboratory-grown
diamonds for 60 years. This continuum — combined
with fundamental research on tens of millions of
natural diamonds — enables GIA to accurately identify
laboratory-grown diamonds and offer reports that fit
the needs for describing these stones.

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Laboratory-Grown Diamonds

Unlike natural diamonds, laboratory-grown diamonds
are grown over a very short period of time — typically
two to three weeks or less. A longer growth period results
in larger crystals, however, steady heat and pressure
must be maintained to ensure the formation of highquality
gem crystals. While laboratory-grown diamonds in
melee sizes are most often encountered in the industry,
larger stones are available and their marketing can
benefit from an association with a GIA Laboratory-Grown
Diamond Report.

Image: Laboratory-grown rough diamond crystals created by the HPHT process
display a distinctly different shape than natural rough diamonds.
Courtesy: New Diamond Technology

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HPHT Diamonds

HPHT laboratory-grown diamonds are grown in laboratories at high pressures and high temperatures.
A diamond seed is used and growth from a flux material (molten metal alloy) takes place over a period of several weeks.

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CVD Diamonds

CVD diamonds are grown at high temperatures and very low pressures in a vacuum chamber. Tabular laboratory grown diamond crystals up to several carats are formed on flat diamond seed plates during growth periods of one week or more.

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Natural Diamonds

Natural diamonds occur only when the right combination of atomic elements meets at high pressures and temperatures about 100 miles below the earth’s surface. The crystal that grows under these conditions has a unique structure we associate with natural diamonds.

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Identification

Identifying laboratory-grown diamonds is complex because their optical and physical properties are nearly identical to those of natural diamonds. However, because of their artificial growth environments, laboratory-grown diamonds exhibit several diagnostic features that allow laboratory testing equpment to readily identify them.

Image: CVD diamond being formed in a CVD vacuum chamber.

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GIA Laboratory-Grown
Diamond Report

GIA offers a Laboratory-Grown Diamond Report that includes the same information as the GIA Diamond Report for natural D-to-Z diamonds.

The information presented in the report is important in the marketing of laboratory-grown diamonds and, being from GIA, a respected, independent third-party, can add value. Like the GIA Diamond Grading Report for natural diamonds, the GIA Laboratory-Grown Diamond Report includes the critical information related to the diamond’s cut such as polish, symmetry and, for round brilliants, a GIA cut grade. These are all factors used to understand the interplay of light patterns that affect the perceived sparkle and beauty of the diamond. Weight and measurements, as well as a GIA plotting diagram, accurately capture characteristics of the stone to aid in its re-identification. GIA laboratory-grown diamond reports include 4Cs color and clarity specifications for laboratory grown diamonds on the same scales as GIA’s grading reports for natural diamonds. The specifications do not correlate to nature’s continuum of rarity. The digital-only reports for laboratory-grown diamonds have a distinct format to fully different from reports for natural diamonds. The laboratory-grown diamond’s girdle is laser inscribed with “Laboratory-Grown” and the GIA report number.

Image: Sample GIA Laboratory Grown Diamond Grading Report

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Information on this page sourced from Gemological Institute of America

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