Ruby: description, properties, and photo

The name «ruby» from ancient Sanskrit means “ratnaraj”, which is translated as «king of precious stones». Bright red color is associated with the strongest human emotions: love, passion, anger. Rubies are mentioned in the Bible. Physical properties of this stone were described by roman scientist Pliny the Elder in the Ist century AD. Ruby was very popular among European royal families and the upper-class. Many medieval europeans wore jewelry with rubies to guarantee health, wealth, wisdom and success in love. As symbol of passion it became an ideal romantic gift. That is why today engagement rings with rubies tend to rise in popularity. Nowadays red corundum shows the fastest increase in comparison with other stones.

Optical and quality properties of corundum are often improved by enhancement. The most common method of enhancement is heat treatment. It is applied to more than 90% of all mined rubies. As a result of heating, the visible characteristics can be improved. The color may become more saturated, it is also possible to remove unwanted shades (such as purple), that reduce the cost of a sample. During heating some typical inclusions also melt, as a result clarity of a stone improves. The cost of uheated samples is about 2-3 times higher than heated samples with the same quality. The cheapest treated rubies are filled with lead glass. Glass filling is a method that applied for improving transparency of low quality stones, usual African. After enhancement opaque rubies can become transparent, but they cost just 1-20 US dollars per carat.