Stone Mania

The ruby makes up one of the four original precious gemstones, the other three being sapphire, emerald and diamond.  Having said that, the term 'semi precious' is no longer favoured by gemmologists who now consider that all gemstones should be referred to as 'precious'.

Ruby is a red gemstone, a variety of the mineral 'corundum' (aluminium oxide).  It is the second hardest natural mineral on Earth with diamond being the first.  Sapphire is also a variety of corundum, ruby and sapphire are scientifically the same stone, the colour is the only factor which makes them different.  The red colour is caused mainly by chromium.  Only red corundum is entitled to be called ruby, all other colours are classified as sapphire.

The close relationship between the ruby and the sapphire has only been known since the beginning of the 19th century.  Up until then, red garnet and spinels were also thought to be rubies.  The 'black ruby' and the 'timur ruby', two of the gemstones in the British crown jewels, were so named because it was believed they were both rubies but in fact they are both spinels!  The name 'spinel' comes from the Greek word for 'spark' and refers to the fiery red colour of this gemstone.  The word 'ruby' comes from the Latin word 'ruber' meaning 'red'.

Colour is the most important factor in determining the value of this precious gemstone.  A good coloured ruby, one that is pure and brilliant and more than three carats, will command an extraordinary price and is said to be the most valuable of all gems even over-taking the diamond!

It is extremely rare to find a perfect ruby, the vast majority have imperfections of some kind.  The reason being is because millions of years ago when they were being created deep inside the core of the earth, chrome was the element which gave them their rich colour, but at the same time it was also responsible for causing a multitude of fissures and cracks inside the crystals.  Therefore only a few were given the right conditions in which to grow undisturbed and to crystallize to form perfect gemstones.

A significant source for rubies during the nineties was a small town called Mong Hsu in the north east of Myanmar (formerly Burma).  When these gemstones were originally found, they were not expected to be suitable for use in jewellery since they displayed two colours, a purple to black core and a bright red periphery.  Only after it was discovered that the core could be turned to deep red by means of heat treatment did they begin to gain great value.

About 90% of rubies are heated to enhance the colour.  It is usually the rough stone that is heated before cutting.  Rubies that are not heated are considered to be very unusual.

Rubies are found in a number of locations worldwide.

Ruby is the birthstone for the month of July and the anniversary gemstone for both the 15th and 40 year of marriage.

It is graded 9 on Mohs scale of mineral hardness.

The following links offer further reading on the ruby