GO 340 Gemstones & Gemology
ES 567 Gemstones of the World
Dr. Susan Ward Aber, Geologist & Gemologist
Emporia State University
Emporia, Kansas USA


Gem Creation

Historically gem possession has been reserved for wealthy, royalty, or high religious leaders. It has always been human nature to want what others possess, so imitation gems have been common for some 4,500 years, in the form of glass, plastic, composites, and treated gems. It is not against the law to imitate, as long as the true identification is given. It is only fraud when imitations, natural or synthetic, are passed off as a more valuable gem at an inflated price.

Is It Real? Created Imitations Synthetic Gemstones Composites Gem Enhancement

Is it real?

Is it real? is a question often posed to jewelers or the knowledgeable gem enthusiast, when people view gems. You do not have to be an expert to answer this question, of course it is real! The real question should be. . . is this gem natural or material created in a laboratory? After the initial answer is given, one should ask, What difference does it make? Imitations and synthetics simulate natural gems and minerals, and they can be quite beautiful. Part of the definition of a gem is the beauty and this is a subjective attribute. If these created stones and imitations are properly labeled as such, and priced accordingly, they can be an affordable alternative to the real thing!

The definition of synthetic is material created in a laboratory using basically the same ingredients found in the natural products (Matlins and Bonanno, 1998, p. 123). Some synthetics have no natural counterpart. Synthetic gems have identical physical, chemical, and optical properties as the natural gem material, for the most part. An exception to this, is in the coloring chemical for some synthetics, which can be different from the natural coloring agent. Even though synthetics may replicate the natural gem, they must be identified and prefaced with synthetic, created, cultured or some origin indicator.

An imitation is an artificial likeness or copy, which could mean a synthetic material or natural gemstone. Imitations are not exclusively synthetics and not all synthetics are meant to imitate! Some synthetics are marketed as a gem in their own right, such as CZ or cubic zirconia. Although it should be prefaced, synthetic CZ, it is often advertised without the synthetic preface; it does have a counterpart in nature, but it is extremely rare. The term imitation is usually applied to glass and plastic although it can refer to natural minerals too. The golden-colored quartz, citrine, has been used to imitate topaz in birthstone rings for so long, that many people have a difficult time accepting natural colors of topaz. Topaz can be colorless, pink, pale brown, sherry-colored (reddish-orange) and less commonly, yellow.

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Created Imitations

Imitations usually resemble the gemstone in color only and are easy to identify as an imitator. "Ancient Egyptians were the first who feigned gemstones with glass and glaze, because genuine were too expensive and/or too rare" (Schumann, 1997, p. 242). One of the earliest imitations to resemble turquoise, prized by Egyptians, and some 7,000 years ago they constructed a turquoise-colored ceramic substance, termed faience, that was used for beads, amulets, pendants, and rings (Matlins and Bonanno, 1997, p. 227). Also, blue glass gems were found in King Tut's tomb (Matlins and Bonanno, 1997, p. 227).

A modern example of faience with a scarab motif.
Specimen provided by Barb Robins. Photo date 3/04, © by S.W. Aber.

Another example of an imitation is hematine, which is both a synthetic and imitation. Hematine is a created simulator of stainless steel with chromium and nickel sulfides. It is made to imitate hematite. The two can be distinguished by a streak and magnetism. Hematite has a reddish-brown streak, whereas hematine has a brown-black streak (this test is destructive though!). Hematine is strongly magnetic, whereas hematite is typically not magnetic.

Photo date 3/02,
© by S.W. Aber.

Photo date 2/02,
© by Berg and Dougan.
A bracelet with hematine and aventurine quartz beads is shown on the left. Note magnet attached to the specimen! A hematite ring and earrings are shown on the right.

Glass is amorphous or a created, inorganic substance which is mixed in a molten form and cooled to a rigid form without crystallizing. There are two main types of glass: crown and flint. Crown glass is made with silica, soda, and lime. It is used for bottles, window and optical glass, and costume jewelry. Flint glass is composed of silica and soda, and lead oxide or other metal oxides replacing the lime. This type of glass has been called strass (or stross) after the Austrian who is credited with its discovery, Joseph Strasser. Flint glass was used to substitute for diamond and because of this, was prohibited in the 18th century by Empress Maria Theresa (Schumann, 1997, p. 242). Glass imitations have been referred to as paste, which is from the Italian pasta meaning dough, "because the ingredients are mixed wet to assure uniformity of the batch" (Hurlbut and Kammerling, 1991, p. 150).

Stones cut from flint glass resembles the gems they are meant to imitate because lead gives a greater dispersion and higher refractive index. Coloring glass is accomplished using a metallic oxide: a purple color is derived from manganese; blue from cobalt; red from selenium or gold; yellow and green from iron; red, green, blue from copper; green from chromium; yellow-green from uranium; and amber glass from a combination of manganese and iron, and no amber at all! "The final color of the glass is also affected by such factors as the type of glass used, the oxidizing or reducing conditions used during manufacturing, and annealing after manufacture. Colorless glasses are made by adding decolorizing agents called glassmaker's soaps; these reduce the greenish tint that otherwise ensues from iron impurities." (Hurlbut and Kammerling, 1991, p. 151) Many cheap glass imitations are foiled, that is the pavilion facets covered with a thin metallic film that acts as a mirror to enhance brilliance and sparkle. Colorless glass can be given a face-up color, or color looking down at the crown, by covering the pavilion with a colored film. A translucent look can be achieved by adding tin oxide.

Some of the more common glass imitations are discussed below. Glass can be beautiful and an inexpensive alternative to natural gemstones.

"Until 1945, Gablonz and Turnau in Czechoslovakia were important centers for the glass-jewelry industry. Then this tradition was taken over by Neugablonz in Allgau, Bavaria." (Schumann, 1997, p. 242). Porcelain, enamel, resins, and plastics also serve as gem imitators. Plastics are formed by heating and/or molding, and called celluloid (cellulose plastic), bakelite (phenol-formaldehyde), plexiglass or lucite (methyl methacrylate resins), polystyrene and polyvinyl resins. The plastic is constructed of long, chainlike molecules called polymers and have a very low hardness. They are sometimes faceted but usually cut en cabochon to imitate gems such as amber, turquoise, jade, and pearl to name a few.

Plastic pearls with paint
coming off. Photo date
3/04, © by S.W. Aber.

Plastic brooch meant to imitate
citrine quartz and jade. Photo date
3/04, © by S.W. Aber.

Plastic cameo meant to imitate
shell or sardonyx. Photo date
3/04, © by S.W. Aber.

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Synthetic Gemstones

The first gemstones to be synthesized occurred in 1838, although they were only of scientific interest (Schumann, 1997, p. 243). A French chemist, A. V. Verneuil, succeeded in producing gem quality synthetic rubies in 1888, termed a flame fusion process (Schumann, 1997, p. 243). The method melts a powdered aluminum oxide with dye additives, and the molten material forms in a pear-shaped boule. Although it has no crystal faces, the crystalline structure is identical to the natural gem. Synthetic blue sapphires were produced by 1910 and sometime later, colorless, yellow, green, and alexandrite-colored sapphires were perfected (Schumann, 1997, p. 243). Star rubies and sapphires were created, by adding rutile to the smelting, in 1947. Synthetic spinel has been produced since 1910, with the verneuil process, although the chemical composition varies from the natural spinel; synthetic emeralds have been produced since the 1940s (Schumann, 1997, p. 246). Industrial quality, diamond synthesis occurred in Sweden and the United States by 1953-4; gem quality synthetics were perfected in the 1970s.

A German chemist, I. Czochralski, developed another synthesis method in 1918, where the boule is drawn out of the smelting after a crystal nucleus has been created. While rotating the boule is continually drawn upward and grows on the underside also. In recent years crystals have been flux-grown, a created method that more closely resembles natural crystal growth. These laboratory-grown synthetics are more expensive to produce than other methods, but can still make a good alternative for consumers who are unable to afford natural gemstones (Matlins and Bonanno, 1998, p. 124).

Some synthetic imitations of diamond include: synthetic rutile (also known as titania or diamonite, created in 1948); fabulite (occasionally called diagem, created in 1953), strontium titanate (SrTiO3); YAG (also called diamonaire, created in 1969), yttrium aluminum garnet (Y3Al4O12); GGG or galliant, a gadolinium gallium garnet, (Gd3Ga5)O12; djevalite, a calcium zirconium oxide (ZrO2/CaO), linobate, a lithium niobate (LiNbO3), cubic zirconia (also known as fianite, phianite, or KSZ), and yttrium zirconium oxide (ZrO2/Y2O3) (Schumann, 1997, p. 242-3, 246). Most recently moissanite, silicon carbide, has become a popular diamond imitation (developed in colorless gem quality in 1996, produced by Cree Research Inc., distributed by C3 Inc.) (Nassau, McClure, Elen, and Shigley, 1997, p. 261).

Visit some created gemstone webpages... Chatham Created Gems, www.chatham.com/, Tairus Created Gems, http://www.tairus.com/main.php, and Ramaura Cultured Ruby, www.ramaura.com.

Chatham has information about:

  • the company history, http://www.chatham.com/The_Chatham_Story.php
  • synthesis from 1947 to today news clippings, http://www.chatham.com/News_Archive.php
  • gallery of possibilities, http://www.chatham.com/Gallery.php
  • Tairus has interesting pages:

  • Tairus, a joint venture between The Russian Academy of Science (Siberian Branch) and Thailand Co LTD of Bangkok, http://www.tairus.com/main.php
  • Hydrothermal Process and How do we do it: production of emeralds and other beryl, rubies, sapphires, white corundum
  • Floating method or Horizontal Crystallization - created alexandrite, ruby, chrysoberyl
  • Created diamonds we grow

    While the founders of Ramaura have retired, the company still has their fascinating story online

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    Composites or Assembled Stones

    Doublets, triplets, and foil backs are composite stones, or assembled from two or more components. Although they can be assembled to deceive, some composite stones were devised to overcome low hardness or durability of a gem. Doublets are made of joining two pieces with a colorless cement or fusion. Triplets are two layers of colorless material joined by colored cement that imparts the overall color, or three layers with a colorless cement. Foil backs are made by applying a mirror-like back to the stone, foil or metallic paint, to enhance the dispersion and brilliance or produce a star-like effect. Genuine doublet or triplets are composed of the same stone on the top and bottom, such as a light-colored beryl joined by a layer of deep green emerald cement. The genuine assembled stone was composed of two pieces of the same gem and used to imitate that gem (e.g., a beryl triplet may consist of two pieces of colorless beryl joined by a green colored cement and meant to imitate emerald). Semi-genuine doublet or triplet has only one portion genuine (usually the crown) or of the species it imitates, such as an emerald imitation with a colorless beryl crown, quartz pavilion and deep green cementing agent. False doublet or triplet is when one (or more) portion is a natural material but none is the gem it is meant to imitate, such as the garnet-glass doublet meant to imitate a ruby or quartz joined with green cement to imitate emerald.

    Garnet and glass doublet was once a commonly encountered composite stone, especially before synthetics became routine. Glass is fused to a slice of garnet, usually almandine. Garnet is found in the crown for color and durability. Garnet and glass doublets have been constructed to imitate garnet or diamond. Other doublet imitations of diamond include: foil-backed glass, rhinestones or foil-backed rock crystal quartz, and colorless spinel or corundum with a pavilion of strontium titanate. Corundum doublets, meant to imitate ruby and sapphire, can be a natural corundum crown glued to a synthetic corundum. Emerald triplets, meant to imitate emerald, consist of natural colorless beryl, colorless quartz, or colorless synthetic spinel, joined with a green cement.

    Opal and ammolite (fossilized shell of ammonites in form of aragonite) are found in thin veins or structures. When used as jewelry, these two gems are commonly found as doublet or triplets to increase its durability and make to most of the rough material recovered.

    Black opal triplet. Photo date 3/04, © by S.W. Aber.

    It is common to cement a thin slice of opal or ammolite to a backing. The backing could be a piece of common opal, black glass, or dyed black chalcedony. The triplet would be assembled the same way, except with a convex cap of clear quartz, glass, synthetic spinel, or synthetic sapphire is cemented to the top of the opal or ammolite section. Visit Ways to Cut Opal, You Tube, hhttp://www.youtube.com/watch?v=sXyBuamNl68&feature=related, and for more information on opal and opal composites:

  • Opal Information, http://www.opal.asn.au/information_nom
  • Opal Technical Information, http://www.grahamblackopal.com/about-opal/technical-opal-info.php and Opal Treatments, http://www.grahamblackopal.com/about-opal/opal-treatments.php
  • Opal Composites - Doublet or Triplet, http://geology.com/gemstones/opal/composite-opal.shtml
  • The Ammolite Gemstone and composite - Korite International, http://www.korite.com/ammolite.html and follow the links for more information on this fossil gemstone and mining.

    Diamond and diamond doublets are called "piggy-back" diamonds. Another diamond doublet involves a diamond crown and colorless quartz, synthetic sapphire, synthetic spinel, or glass on the pavilion. Jadeite triplets are constructed of a colorless jadeite hollow cabochon glued to a flat base, with the hollow dome filled with a green jellylike substance (Hurlbut and Kammerling, 1991, p. 162). Imitation cat's eye could be assembled from a hollow cabochon of synthetic corundum, filled with fibrous ulexite (often called TV stone!), glued to a base of a shallow cabochon of synthetic corundum. The opal imitation could be a cabochon of colorless glass or plastic glued to a base of mother-of-pearl shell.

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    The material for this section came primarily from:

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    This page originates from the Earth Science department for the use and benefit of students enrolled at Emporia State University. For more information contact the course instructor, S. W. Aber, e-mail: esu.abersusie@gmail.com Thanks for visiting! Webpage created: November 15, 2000; last update: Septebmer 30, 2012.

    Copyright 1999-20120 Susan Ward Aber. All rights reserved.