Inorganic Gemstones

Home

Synthesis & Synthetic

The International Confederation of Jewellery, Silverware, Diamonds, Pearls and Gemstones (CIBJO) define synthetics, imitations and composite gemstones as follows:

  1. Synthetic Stones are crystallised or recrystallized products whose manufacture, by which ever method, has been caused completely or partially by man. Their physical and chemical properties and/or their crystal structure essentially correspond to their naturally occurring counterparts.
  2. Imitation Stones are simulations of natural or synthetic stones, products made entirely or partially by man. These stones imitate the effect, colour and appearance of natural gemstones or synthetic stones without possessing their chemical composition and/or their properties and/or their crystal structure.
  3. Composite Stones are crystalline or amorphous bodies composed of two or more parts assembled not by nature, but by cementing of the pieces or by other artificial methods. Their components may be either natural gemstones or other minerals, or synthetic stones or a chemical product.
  4. Reconstructed stones are artificial products, manufactured by melting, bonding, or fusing materials to form a coherent whole. Natural and synthetic chips or waste materials are commonly bonded, as is seen in turquoise, coral etc.
  5. Synthetic Overgrowth: In 1960, Johann Lechleitner of Austria synthesized a hydrothermal overgrowth emerald on a natural beryl seed. These emeralds were often referred to as Lechleitner emeralds or as sandwich emeralds (in the case of synthetic emerald overgrowth on a colourless seed). Over the years Lechleitner synthesized a number of different overgrowth stones with the finished products having various colours.
  • Overgrowth is a process by which feed material is allowed to grow on a seed crystal by a man made process. The seed crystal may be natural or synthetic.
  • In this process, a layer by layer growth takes place on the seed crystal. In the case of overgrowth emerald, this results in:
    • parallel lines along the length of the stone
    • a chess board pattern of fine fingerprint like inclusion or fractures which are observed in the synthetic overgrowth portion only.
    • Euclase or phenakite crystals can occur at the junction within the synthetic overgrowth.
  • In the case of Lechleitner corundum (overgrowth ruby, blue & yellow sapphire), the internal pattern exhibited:
    • wispy veil - like fingerprint inclusions
    • flux fingerprint inclusions or sometimes curved growth lines in the synthetic portion
    • characteristic square and rectangular appearance of the fingerprints (Lechleitner-design)
  • Some examples are:
    1. Synthetic Pink Corundum over Verneuil Colourless corundum.
    2. Synthetic Ruby over Verneuil Ruby
    3. Synthetic Ruby over Natural Corundum

Synthesis of Gemstones: In the earliest recorded attempts to synthesis gems, natural stones were buried in the ground in the hope that they would reproduce or grow large over the years. Experiments by scientists have tried to simulate the natural growth conditions which exist at the time of crystal formation. In recent years, research in crystal growth has led to many important advances in gem synthesis.

There are three major methods which are employed in the commercial productions of synthetic gemstones.

  • Flame Fusion Process (Verneuil)
  • Flux Fusion Process
  • Hydrothermal Process

Some other methods employed to produce sythetic gemstones are:

  • Czochralski Process (Crystal Pulling Technique)
  • Skull Melting Process
  • Gel Growth Process
  • Ceramic Techniques (not true sythetics)

Did you know?

Jewellery is one of the most bought products online. An estimated $1 billion USD of diamonds are bought annually via the Internet. Over 40 million people use the Internet to trade!

In Germany, the garland of ambers is hung around the necks of the infants, so that their teeth might come out without much trouble.

In Turkey, people fix a piece of amber in the hubble-bubble, dogged by an age old belief that the presence of the jewel would destroy all the germs and no disease would spread, even after many have dragged their puffs from it.

In Greece, people think if wine is poured into the cups made of amethyst, one does not get drunk after drinking that.

In Rome, a talisman having coral pieces is considered very auspicious to quell the bad spells of evil look. The Romans were in the habit of hanging chains made of ancient coral pieces from the cradle of the infants to protect them from evil effects.

In China, people wear rings studded with tiny conch or oyster shells as they believe it cures all aches such as stomach ache, worms and like.

In India, pendants made of silver and studded with pearls are hung from the necks of the children to save them from any bad effects.

Greeks still believe, if women wear blue sapphires then no sense of immorality would pollute their mind nor can any fear of the supernatural can trouble them.

The Pope Innocent III had circulated an order asking all the priests wear blue sapphire, so that morality can be strengthened.

It is said about turquoise, that when the stone changes its color into yellow, it actually signals bad times to the person who wears it.

It is believed that a turquoise gifted to a friend or a lover turns his or her life into one of happiness and good luck.

Poll