Blue Sapphire Oval Selection 0.4-0.6 ct

Sapphire is a gem quality mineral corundum of any colour except for red, which is called ruby.

Chemically it is an aluminium-oxide crystallised in the trigonal system. The name sapphire is traditionally associated with blue gems. There are many other colours it can have, generally described as fancy sapphires. Possible hues include- colourless, yellow, greenish, pink, purple, orange, brown, black and the most expensive and famous of fancy sapphires, pink-orange stones named Padparadscha.

When considering a sapphire purchase, colour is the most important factor. For blue stones it is a strength and purity of primary blue hue that is a basis for valuation. It can be increased by a slight percentage of violet or decreased by green or grey mask. For fancy sapphires it is a general strength of colour decreased by grey or brown tones. Inclusions are of secondary consideration as they are present in most sapphires, plus they are not necessarily a bad thing as they help with identification of possible treatments and origin of the gemstone.

Synthetic sapphires were already available at the end of 19th century. They are widely used in commercial level jewels today.

Treatments used on sapphires include a traditional heat treatment, practised already in Roman times. It can improve colour and clarity of the stones. It is completely safe and permanent practice. There are also more modern ways of improving sapphires. Like a beryllium treatment in which stones are heated to just below their melting point, to allow beryllium to penetrate their structure. This treatment changes the colour dramatically and can vary in depth from shallow to a one that penetrates gem completely. Berylium treated stones are considerably cheaper than natural or only heated ones. That treatment is usually not so easy to prove and may require a lab test. Other possible treatments include fracture filling, which nowadays is widely used for treatment of corundum.

Sapphire has hardness of 9 and is very durable. It can be cleaned in ultrasonic cleaners as long as there are no liquid inclusions but steam cleaners are not recommended. The best way to clean your stones is to use a soft toothbrush under running water and dry them with a soft cloth.