Inorganic Gemstones

Home ยป Visual Identification

Transparency

Transparency or Diaphaneity is a property of the substance to transmit light, or, in other words, the ability of a stone to allow light to pass through it in varying degrees.

The amount of absorption of light by a gem varies from a very small fraction absorbed in transparent stones such as diamond, to almost complete absorption by black jet. Thus, if light were allowed to pass through a gemstone without any distortion or absorption, it would be termed a perfectly transparent stone.

Transmission of light depends upon:

  • The structure of the stone.
  • Colour: Deeply colored stones will pass less light than lightly coloured ones.
  • Thickness: Thicker stones will allow lesser transmission than thinner stones.
  • The presence or absence of imperfections and inclusions.

The degree of transparency of a gemstone is roughly classified as follows:

  • Transparent (Tp): An object viewed through the stone appears with sharp, clear and distinct outlines, e.g. finest qualities of diamond, corundum, beryl, etc.
  • Semi-Transparent (S-Tp): The viewed object appears blurred with not so clear and distinct outlines even though a considerable amount of light is transmitted, e.g. finer qualities of jade, corundum, quartz, etc.
  • Translucent (Tl): The object cannot be viewed through the stone but some amount of light is transmitted e.g. chalcedony, moonstone etc.
  • Semi-Translucent (S-Tl): Slight light transmission is seen through thin sections or the edge of the stone e.g. onyx, obsidian, chrysoprase etc.
  • Opaque (Op): No light can pass through the stone. In the strictest sense, these are mainly those substances such as pyrite, hematite etc. Since any other substance in thin sections transmits some light. When cut in ordinary thickness gems such as black chalcedony, lapis lazuli etc. are opaque.

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