Inorganic Gemstones

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Hydrothermal

This method is closest to that of nature. This process was first used for the synthesis of Quartz for use in industry. In 1960, the first hydrothermal emerald was brought by Lechleitner. Over the years this process has advanced to such an extent as to almost completely simulate natural emeralds. The major differences still lie in the study of inclusions and structural differences.

How gemstones are synthesized by hydrothermal process?

  • A steel autoclave or bomb (in effect, a pressure cooker) is used.
  • Crystals are grown in a sealed environment at very high temperatures and pressures.
  • Seed crystal wafers (plates) of the desired material are hung in the upper portion of the vessel and lumps of powder of the desired material (nutrient) are placed in the bottom.
  • The vessel is partially filled with water and sealed.
  • Heat is applied from the base and the material dissolves in the water, forms as a supersaturated solution, rises to the top of the autoclave until all the available material has been deposited on the seed crystal wafers.
  • Large well formed crystals are produced. Quartz crystals in excess of eighteen inches in length and 1.5 to 2 inches in diameter are produced.
  • The size of the end product depends mainly upon the seed water, the amount of feed solution, and the length of time involved.

Gemstones synthesized by hydrothermal with its identification.

  • Synthetic Quartz:
    • Synthetic quartz has similar physical and optical properties as the natural counterparts.
    • Synthesized in colourless, smoky, amethyst, citrine, parti-coloured (ametrine), blue and green varieties.
    • Most synthetic quartz is untwined and therefore exhibits circular interference colours when viewed under cross polars along the optic axis direction.
    • Synthetic quartz produced using natural twinned quartz seed crystals tend to exhibit partial Brazil law twinning in a flame like manner when viewed under cross polars along the optic axis direction.
    • Under magnification color zoning, whitish pinpoint inclusions - bread-crumb inclusions and seed plate inclusions are seen.
    • Synthesized by Sawyer Research Products (U.S.A), Russia etc.
  • Synthetic Emerald:
    • Synthetic emerald has similar physical and optical properties as the natural counterparts.
    • Under magnification veil-like inclusions, nail head spicules, parallel growth structures, chevron (growth features), hound's tooth structures, seed crystal, phenakite crystals, hexagonal and triangular platelets are seen.
    • Synthesized by Linde / Regency, Biron, Russia, Lechleitner, Agee, Tairus and Malossi.
  • Synthetic Ruby / Sapphire:
    • Synthetic ruby / sapphire have similar physical and optical properties as their natural counterparts.
    • Under magnification veil-like inclusions, nail head spicules, growth zoning, chevron (growth features - Christmas tree-like effect), seed crystal, hexagonal and triangular platelets are seen.
  • Synthetic Beryl:
    • Synthetic beryl has similar physical and optical properties as the natural counterparts.
    • Synthesized in a number of different colours - blue, pink, yellow, violet etc.
    • Under magnification veil-like inclusions, nail head spicules, parallel growth structures, chevron (growth features), hound's tooth structures, seed crystal, phenakite crystals, hexagonal and triangular platelets are seen.
    • Synthesized by Russia, Crystal Research Co. (Australia), etc.

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.

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