SYNTHETIC STONES

By- JUHI D. VORA

A Brief Historical Perspective on Gemology

• Gemstones have fascinated mankind since civilization. They are often associated with symbols of status, wealth and supernatural powers and for the past hundred years they are associated with the ultimate expression of love. Historically kings and queens, rajahs and sultans, men and women of immense wealth and powerful mandarins of influence are collectors of rare gemstones.

• The science of gemology is concerned with the study and identification of gemstones and

gem materials.

Over the past 100 years gemological

technology has accelerated in parallel with the creation of lab grown synthetic gemstones. Almost every known gemstones has been

synthesized and this has made the task of a gemologist a more demanding and exact one. History is full of remarkable mistakes where

gemstones are wrongly identified based on colour and luster itself - the most famous one being the Black Prince Ruby set in the Imperial State Crown of England. For centuries the sparkling red stone was thought to be a priceless ruby until modern gemological instrument made it possible to identify the stone as a rare spinel of unsurpassed beauty. Had it been a ruby its worth would be priceless.

A Brief History of Synthetic Gems

From the earliest records in human history, attempts have been made to imitate precious gems. The ancient Egyptians used convincing colored glass and porcelain to mimic their most sacred stones, lapis, turquoise and coral. Mining, in ancient history, had profound limitations, not the least of which was the limited amount of travel most cultures accepted as a reality of their lives. Until the end of the 19th Century, glass and porcelain remained the mediums for imitating precious gemstones. Chemical elements were discovered at the end of the Middle Ages. Developments in analytical chemistry were widespread in the 18th century. Technological advancements exploded in the 19th Century and provided the techniques for actually synthesizing gemstones. Early chemists were attempting to manufacture a synthetic product with the hardness and toughness of gems which would have industrial applications. Early synthetic gems were seen as an excellent and inexpensive alternative for watch makers, not jewelers!

Synthetics Synthetics are man-made gem

products. The Federal Trade Commission is quite specific in forbidding the use of the term "gem" or "gemstone", unless that product is solely and exclusively the work of Nature. Acceptable terminology for synthetics is variable, but would include product labels similar to the following: "synthetic gemstone", "laboratory-grown ruby", "cultured pearl", "created emerald", "man-made sapphire", "reconstituted turquoise". Synthetics can be exact copies of natural gems, or they can be unique materials which are not found in Nature.

Synthetic Gems Include Ruby Sapphire (all colors) Emerald Aquamarine Red Beryl Spinel Quartz (all colors including Amethyst,

Citrine and Ametrine) Alexandrite Opal Fire Opal Forsterite (used as Tanzanite imitation) Peridot (not commercially available)

SYNTHETIC RUBY

SYNTHETIC DIAMOND

SYNTHETIC EMERALD

SYNTHETIC BLUE SAPPHIRE

SYNTHETIC QUARTZ

SYNTHETIC AMETHYST

SYNTHETIC MYSTIC QUARTZ

SYNTHETIC BERYL

SYNTHETIC CORAL

SYNTHETIC TURQUOISE

SYNTHETIC SPINEL

SYNTHETIC WHITE OPAL

GEM CRYSTALISATION PROCESSES

MELT PROCESS-1) Flame Fusion2) Czochralski "Pulling"3) "Skull" MeltingSOLUTION PROCESS-1) Hydrothermal2) Flux VAPOR PROCESS-1) CVD (Chemical Vapor Deposition)

SIMULANTS (Artificial Products)Artificial Products are defined as

crytalline gems produced by ay artificial process which have no natural counterparts. Their primary function is to imitate other gems, but their physical and chemical properties are not related to the stones they imitate.

Artificial Products Include Moissanite Strontium Titanate Yttrium Aluminum Garnet (YAG) Gadolinium Gallium Garnet (GGG) Cubic Zirconia

WHITE ZIRCON

STRONTIUM TITANATE

YTTRIUM ALUMINIUM GARNET (YAG)

CUBIC ZIRCONIA

MOISSANITE

SYNTHETIC RUTILE (TITANIA)

NATURAL GEMS AS SIMULANTS

It is very common for one natural gem to be used to imitate another of similar appearance. For example serpentine, aventurine quartz and hydrogrossular garnet, all have long histories as jade simulants. Likewise, bone is a common substitute for ivory, and white zircon has long been enjoyed as a natural diamond simulant. Red spinel commonly is substituted for ruby, sodalite for lapis lazuli, and copal for amber.

BONE CARVING (IVORY)

RED SPINEL (RUBY)

COLORLESS CUBIC ZIRCON (DIAMOND)

YAG (EMERALD)

SODALITE (LAPIS LAZULI)

Partially FOSSILED Tree Resin(AMBER)

MAN MADE SIMULANTS

Glass: Although its historical roots go way

back, glass is still one of the most popular gem simulants today. Glass, itself, is an amorphous material, but its main raw material, silica sand (quartz), is crystalline. Two quite different forms of glass are used to simulate gems: crown glass and flint glass.

• The moral of the story for the gemologist is: "Always suspect that the "gem" you are looking at is glass--> and test for this possibility."

A glass jade simulant showing typical bubbles under

magnification.

AVENTURINE GLASS

A glass faux PEARL showing scratches in the painted-on

surface coating.

Four colored GEMSTONE (China)

Plastic: Plastics are quite soft, with

hardnesses ranging from 1.5 to 3, and both the refractive index and specific gravity are low.

Glass is a more convincing simulant of transparent gems, but plastic does a good job imitating translucent and opaque stones like amber, turquoise and coral. Certain optical properties of some types of plastic can be utilized to do a good job of simulating phenomenal gems like opal and moonstone.

Imitation OPAL, Faux PEARL, Plastic MOONSTONE.

Why make synthetics? Outside their use as synthetic or simulant gems, physicists and chemists make large quantities of both copies of natural gems, and totally artificial ones, for industrial and research purposes. At present over 90% of the diamond abrasives ("bort") for industry, used in everything from the saws that cut through pavement, to dentists' drills, are synthetics produced in a laboratory. Laser and electronic technologies depend strongly on the properties of laboratory created crystals. Even a cheapie "quartz" watch has, at its heart, a synthetic quartz crystal. Lasers based on synthetic crystals are used in medicine in a wide variety of ways from surgery to removing tattoos to improving vision.

MAGNIFIED PICTURE OF SYNTHETIC DIAMOND CRYSTALS USED AS ABRASIVES

Beyond these practical applications, laboratory study and production of synthetic mineral crystals allows scientists to test hypotheses, and extend knowledge in many areas of the physical sciences.

Should you buy a synthetic gemstone or jewelry with

created stones over the natural gemstone choices?

I would recommend going with your own personal preference. If you want a piece of jewelry with a flawless, perfect gem, then go with the synthetic gemstone. Also, if cost is a deciding factor. As a collector/investor my preference would be for the natural gemstone. It's value and appreciation factor will be much greater, flawed or not. But as an adornment in jewelry a synthetic gemstone makes for a gorgeous ring, earrings or pendant at an affordable price.

CONCLUSION The science of gemology also made it possible to

identify natural gemstones which have been ‘treated’ to enhance its beauty and mask its flaws, gemstones whose black inclusions are busted with laser and filled with clear polymer, surface coating to give it a vivid hue, irradiation to change its body color to a desired rarer color and the more primitive method of dying to improve the appearance of a gemstone. A deeper understanding of gemology would also enable a gemologist to identify the origin of a gemstone. Unlike the olden days where the identification of a gemstone was based on the whims and personal experience of the dealer or the soothsayer, gemology is now an exact science due to the various scientific instruments available and the great body of knowledge accumulated and dispensed over the years by various international gemological institutions.

THANK YOU