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Gems from the Lab


Gems from the Lab

Ah, the romance of the diamond, pressed into existence by Mother Nature over thousands of years. Its history is a metaphor for love's endurance, just as its brilliance suggests the spark in the beloved's eyes. But what if the suitor could give a ring with a brilliance born in a laboratory?

One of the more remarkable feats of technology in the jewelry industry is the making of high quality gems in laboratories. For decades emeralds, rubies, sapphires, opals and other popular stones have been synthesized in labs and sold by jewelers. Now, within the past few years, gem-quality synthetic diamonds have also reached the market.

The most common method for making synthetic diamonds involves subjecting carbon to high pressure and high temperature (HPHT), basically mimicking the way nature produces diamond. The process takes about 100 hours for diamonds to develop, compared with nature’s 3 billion years. A newer method, called chemical vapor deposition (CVD), transforms carbon into plasma, which then precipitates onto a substrate and is left to grow.

Synthetic diamonds should eventually sell for about 5 - 10% (maybe less) of the price of a natural gem, and vastly more people can afford them. The HPHT diamonds come out faintly colored, rather than clear, so the manufacturers use various means to intensify the color and sell the gems as intensely colored “fancies.”

Many jewelers are still reluctant to carry lab-grown diamonds, saying that customers do not understand the distinction and think they are being cheated. Others say that good quality synthetics are as beautiful as their natural counterparts and are far less expensive. "It's still fine jewelry," asserts one jeweler.


Since the price difference between natural and synthetic diamonds is so great, disclosure of synthetics is crucial. Ideally, the selling jeweler examines each stone and verifies that it is natural or synthetic. However, most jewelry retailers do not have a gem lab in which to examine stones or the expertise to distinguish synthetics from naturals. These retailers must depend on the word of their gem suppliers—who may be just repeating what they were told. For this system to be reliable, there must be no break in the chain of disclosure: diamond manufacturing lab, wholesaler, jewelry manufacturer, supplier, jeweler retailer, customer.

Ultimately, it is the seller’s responsibility to tell a purchaser that a diamond is synthetic. In a survey reported in one jewelry trade magazine, 97.4% of the responding jewelers said they disclosed synthetic gems verbally, but only 50.4% disclosed on the sales receipt.

One must wonder about the nature of a merely verbal disclosure. Did the seller explain that synthetics have about 5% the value of natural diamonds? Perhaps the seller discussed how cultured pearls have virtually replaced natural pearls in today’s market. Such a comparison is misleading, since diamonds will not necessarily follow this path.

It is an open question whether a synthetic gem would be so identified on the insurance appraisal, as it certainly should be.

Buyer’s Tip

Require the seller to state in writing (on the sales slip and appraisal) that the diamond is either natural or synthetic. If he is reluctant to do so, it may be because he has not examined the stone and doesn’t know for sure, or because he knows it is synthetic and doesn’t want you to know or doesn’t want you to have that in writing.