Inorganic Gemstones

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Elements of Symmetry

Crystal Symmetry refers to the 'balanced' pattern of the atom structure. In well developed crystals, this 'balance' of structure is evident in their outward shape and if a large number of such crystals are examined, it will be found that different species vary in the symmetric, arrangement of their faces. There are three basic elements of symmetry - centre of symmetry, plane of symmetry and axis of symmetry.

A centre of symmetry exists when every face of the perfect crystal is parallel to a similar face diametrically opposite to it on the other side of the crystal.

A plane of symmetry is an imaginary plane dividing a body into two parts, so that each half is the mirror image of the other. If a crystal was cut in half along such a plane and then the cut surface was to be placed against a metal mirror, the reflection would appear to replace the missing half. The number of possible planes of symmetry in a crystal varies from nine (in a cube) to none at all, according to the species of crystals.

An axis of symmetry is an imaginary line through the crystal about which the crystal can be rotated to represent the same appearance two, three, four or six times in one complete rotation of 360°.

  • Axis of two-fold or binary or digonal symmetry: During a complete rotation, a similar face appears twice in the same position.
  • Axis of three-fold or trigonal symmetry: During a complete rotation a similar face appears thrice in the same position.
  • Axis of four-fold or tetragonal symmetry: During a complete rotation a similar face appears four times in the same position.
  • Axis of six-fold or hexagonal symmetry: During a complete rotation a similar face appears six times in the same position.

Although for clarity one set of faces is considered in these examples, all other faces in the figures fall similarly into repeat positions i.e. the whole crystal presents a like appearance two, three, four or six times in the revolution.


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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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