Reconstituted, Reconstructed, Recrystallized, Regrown – again!

Kurt Nassau, Ph. D., of Nassau Consultants, Lebanon, N.J., who retired after 30 years with AT&T Bell Labs, Murray Hill, N.J., has long studied and written on the treatment and synthesis of gemstones.

The first synthetic gemstone ever to appear in the jewelry trade, the “Geneva” ruby of 1886, initially was called natural ruby but quickly proved to be a synthetic made by melting. Next it was called “reconstituted” or “reconstructed” and said to be made by fusing together chips of natural ruby. This claim was finally disproved in a detailed study which Robert Crowningshield and I published in 1969 (Lapidary Journal, April 1969, page 114). Photo 2 shows three such early “Geneva” synthetic rubies; photo 1 shows the internal structure.

Over the past century, many additional synthetics have appeared with similar claims. Recall, for example, the “Pool” emeralds of 1988, distributed from Australia with an intense marketing campaign which implied that some of this material was a natural product. The company claimed that a “unique and secret process” was used to convert lower-grade natural emerald from the Pool mine into high-quality emerald. In due course it was shown that the “Pool Emerald” was merely a Biron-type hydrothermal synthetic emerald (see K. Nassau, “Synthetic gem materials in the 1980s,” Gems and Gemology, Spring 1990, page 50.)

Quite recently A.G. Japan Ltd. of Tokyo introduced another hydrothermal emerald product as “AGEE Emerald, refined and recrystallized.” This is said to be made from crushed natural emerald purified by laser technology and then recrystallized hydrothermally. It, too, has been identified (by C.C. Millisenda, Z. Dt. Gemmol. Ges., March 1995, page 7) as a synthetic emerald closely resembling the Biron-type hydrothermal product.

And now we have the “TrueRuby,” said to be “created by recrystallization of 100% naturally occurring ruby purified to museum color and clarity by our unique recrystallization process.” This wording comes from the “Affidavit of Authenticity & Lifetime Replacement Guarantee” supplied with each stone by the TrueGem Company at a price of over $200 per carat. Photo 3 shows a “TrueRuby”; a “TruePinkSapphire” also is produced.

Why such claims? Why are products marketed with such claims? Why are they presented as superior to “ordinary” synthetics? An analysis suggests marketing claims focus on four areas:

  • The claim that a recrystallized stone is superior because it is made from natural gemstone material rather than from purified chemicals.

  • The claim that a recrystallized stone is superior because it contains the same impurities that occur in a natural gemstone in about the same amounts. This sup-posedly results from using the natural material as feed and also is supposed to permit identification.

  • The claim sometimes made that some original inclusions of the natural material are preserved in the stone by incomplete melting. Such a product is supposed to be superior since these inclusions are closer to the natural and also can confirm a natural origin.

  • The implied claim that there are some “sympathetic magic” aspects. Many believe that natural gemstones have magical properties. Magic works by close contact, a process attributed to “sympathy.” Hence the closer a synthetic is to the natural, the more likely it could have acquired some of the magical properties of the natural.

Answering the following four questions may help put such claims into perspective:

  • Is recrystallization of a natural gemstone technically feasible?

  • Can claims for the recrystallization of a natural gemstone be confirmed by examining the product?

  • Is recrystallization of a natural gemstone economically viable?

  • And what is the correct nomenclature for such a product?

History is an invaluable guide for interpreting new situations. Let us consider each of these eight items in light of gemological and crystal-growing experience accumulated over the decades and see how they apply to the “AGEE Emerald” and the “TrueRuby” and “TruePinkSapphire” products.

1. Is natural gem feed better than a purified chemical feed in synthetics?

First, remember that all feed material ultimately derives from natural minerals mined from the earth. This feed material is melted (for the Czochralski pulling used for the “TrueGem” products) or dissolved (in the hydrothermal growth used for the “AGEE” product). Either process destroys the identity of the feed material. Note, however, that all atoms of aluminum, oxygen, beryllium, chromium, etc. are exactly the same, wherever they originated.

Two special considerations apply to synthetic emerald. First, essentially all purified beryllium oxide – used as part of the usual feed for emerald synthesis – does originate from mined beryl or emerald. However, all emerald synthesis processes seem to require that the reacting feed reagents be kept apart in a special way until the crystal actually forms. (See K. Nassau, Gems Made by Man, GIA, page 15.) This alone would appear to prevent the use of emerald feed in all but small amounts.

Let’s look at a different example. Both breathing and decay release a person’s carbon into the atmosphere as carbon dioxide. Plants use this carbon, then are consumed in part by animals and ultimately by us. As a result, at least a few atoms of carbon in each of our bodies once were part of famous religious leaders of the past, of Newton, Shakespeare, Beethoven, and so on. Unfortunately, this in itself does not make us superior. Neither do I believe that natural gemstone feed material makes a synthetic superior.

2. Do the impurities in a natural gem feed material make a synthetic superior and permit it to be identified?

This is a most curious claim. When we compare natural gemstones from different localities, we usually prefer the ones with fewer impurities. Why should synthetics be different?

Yet the situation technically is quite complicated. If we want an impurity level of, say, 100 ppm (parts per million) iron in a ruby grown from melt, we usually need to add a different amount – perhaps 1,000 ppm iron (if the “distribution coefficient” is 1Æ10) – to the melt. The amount of any one impurity required usually varies with the oxygen content of the atmosphere; the amounts also vary from one impurity to another. So, if you melt a ruby with a given set of impurity concentrations, the ruby crystal grown from this melt unavoidably has a different set of impurity concentrations.

The atoms of impurities in natural ruby are identical to the atoms in bottles of similar purified chemicals on any chemist’s shelf. But it is much easier to use the bottles to add a desired set of impurities to the usual highly purified feed material. I know of no chemical analysis or gemological and other physical properties that could distinguish the resulting synthetic ruby from one grown from actual natural ruby.

The TrueGem Company states that a multi-stage purification process is applied to the natural ruby claimed to be used as a feed material. My 30-plus years’ experience of crystal growth suggests that adding more impurities before final growth begins is the only way to obtain “natural” color and impurity distribution in a crystal grown from feed subjected to such a purification procedure.

I also am quite uncomfortable with the chemical analyses presented in the TrueGem Company’s literature. For example, if I sent a “typical synthetic ruby” for analysis and received a result showing 0.1 ppm or more of bromine, mercury, osmium, tellurium and zinc, I would suspect contamination. And if there is not even 0.01 ppm of iron or titanium along with these other impurities, such an improbable set of numbers definitely would prompt me to request a re-analysis.

In summary, analysis of a synthetic ruby can establish the types of impurities and their concentrations, but cannot indicate whether these impurities came from a natural ruby feed or from a shelf of purified chemicals. But if the impurity pattern is the same as that of natural ruby, you can be sure that at least some of these impurities came from the shelf.

3. Can incomplete melting preserve original inclusions?

This was claimed for the original 1886 “Geneva” ruby, supposedly made by partially melting together chips of natural rubies to obtain a “reconstituted” or “reconstructed” product. Early observers didn’t see any such inclusions, but did note plentiful gas bubbles (see photo 1), typical of a fused product. The photo also shows strongly curved growth banding, characteristic of this early pre-Verneuil flame fusion-type of process; these bands sometimes meet at angles. In additional experiments using the supposed process (K. Nassau, Lapidary Journal, May 1969, page 313), pieces of North Carolina ruby were only partly fused together. The result can best be described as a mess, as shown in photo 4. Because ruby has a unique crystal axis (the c-axis or optic axis), it obviously is impossible to produce a single crystal by only partially melting pieces with random orientations.

The inclusions and other growth features observed in various reconstructed, reconstituted, recrystallized or regrown products are characteristic only of the synthesis process employed and do not show what feed material was used. The original “Geneva” synthetic ruby shows Verneuil-type inclusions and structures; the “Pool” and “AGEE” synthetic emeralds show typical hydrothermal ones of the Biron type; the “TrueGem” synthetic ruby shows typical Czochralski ones.

4. Do these products have magical properties?

It is interesting to consider where the concept of gemstones’ magical properties originated. Chemists, then called alchemists, began to understand some of the reactions of ordinary substances, such as salt, sugar, alum, metal ores, etc. in very early days. But gemstones were totally resistant to the heat and reagents then available. Hence they concluded that gems must have had a supernatural origin and could, therefore, have magic properties. Note that only the aristocracy and members of the church wore gemstones in those days.

Most magic was “sympathetic,” that is acquired by sympathy from contact with some object. If one wanted a pearl to be white, one dipped it into the white milk from a white dog, thus producing by sympathetic contact the characteristic of whiteness. Applying these same concepts to the hard and resistant “supernatural” characteristics of beautiful gemstones led to the attribution of magical properties. Only from the 18th century on did chemical investigations become sufficiently sophisticated to demonstrate the true nature of gemstones and lead, in due course, to their synthesis.

I personally feel that a man-made synthetic has exactly the same magical properties, if any, as a natural gemstone. But I think those for whom only a natural stone is magical would consider a synthetic – whatever its feed material – merely a man-created and therefore non-magical product.

5. Is recrystallization of natural gemstones technologically feasible?

Here the answer clearly is “yes.” Given an adequate quantity of sufficiently pure natural gemstone material, most synthesis processes will work – with certain exceptions such as the emerald discussed in Item 1 above. If the natural material is too impure, chemical purification or a series of meltings, as claimed in the “TrueGem” process, may be a sufficient preliminary step. However, additional colorant (chromium oxide, in the case of ruby) and other impurities probably would be needed for the grown synthetic to match the original color and impurity content of the natural gemstone.

Nevertheless, using highly purified feed material greatly simplifies a gem grower’s task. It provides a consistent starting point and, if impurities need to be added, this too can be done consistently. Of course, an insignificantly small amount of natural feed can always be added without interfering with the growth process.

6. Can the claims for recrystallization be confirmed by examining the product?

Here, as far as I know, the answer is “no.” As discussed in Item 2 above, chemical analyses or physical properties cannot distinguish between a synthetic grown from natural feed and one grown from the usual highly purified feed material with impurities added. Inclusions and growth structures merely reflect the synthesis process used (see Item 3).

Accordingly, a purchaser must rely entirely on the integrity of the manufacturer (or his publicity department) as to the type and quantity of feed actually used.

7. Is the recrystallization of a 100% natural gemstone economically viable?

That depends in part on supply and demand. But even if there were a good supply of high-purity natural gemstone for feed and a good demand for “recrystallized” synthetic product, I think the answer still would be “no.”

Both the “TrueGem” and “AGEE” manufacturers say their feed must go through several purification steps. Such steps must be both time consuming and expensive. And if, as I believe, impurities must be added to match the color and impurity distribution of natural gemstone, the material no longer meets the concept of a total recrystallization, or the claim of “100% naturally occurring.”

I myself do not believe that a “true” recrystallized product containing no added purified chemical feed and/or impurities could be made. And even if it could, I do not believe that such a product could be economically viable, even at several hundred dollars per carat.

8. What should such synthetics be called?

Finally comes the question of nomenclature to be used in marketing. The 1991 CIBJO international rules do not permit a designation such as “recrystallized ruby” without using the term “synthetic.” In fact, Article 8 appears to forbid use of terms such as “recrystallized” under any conditions.

“TrueRuby” is manufactured by the ICT Company (International Crystal Technology ) of Shelby, Mich., a long-time major maker of synthetic cubic zirconia and other synthetic crystals. But the apparently newly-formed “TrueGem” Company of Las Vegas handles marketing. The name “TrueRuby,” derived from the name of the company, suggests that there is something “true” about such a synthetic. This almost certainly contravenes the spirit if not the letter of the American FTC Guides for the Jewelry Industry.

In conclusion: Whatever the formal rules, I believe that the products under consideration can never be considered “100% natural” in any meaningful sense. No tests can establish the presence of any natural ruby used as a feed material. In view of the nomenclature considerations, what we have is simply one more synthetic emerald, one more synthetic ruby and one more synthetic pink sapphire. They should be so designated, in my opinion.

Acknowledgments: I am grateful to Edward Lewand of Consultant Appraisal Services Inc. of Sayvill, N.Y., and Robert C. Kammerling and Maha DeMaggio, both of the Gemological Institute of America, Santa Monica, Cal., for their kind assistance.