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Sapphires are naturally occuring, precious gemstones and belong to the mineral family corundum. Second in hardness only to diamonds, they are formed from a combination of aluminium and oxygen*. Uncut, natural sapphires have slim, barrel shaped (trigonal) crystals which are usually rough or rounded.
*chemical formula Al2O3
Sapphires are rare gemstones and can be described in terms similar to that of diamonds i.e. colour, carat size, cut and clarity, commonly referred to in the diamond trade as the four C's. However, unlike diamonds, sapphire properties are more variable. There are no single, internationally recognised standards. Conversely, it is this variation which makes each natural sapphire so fascinatingly unique, no two stones are ever exactly alike. Country of origin is deemed important in higher quality sapphires, so it might be thought of as the fifth C.
Many people think of sapphires as being blue, but they may also be pink, yellow, orange, orange-pink ('padparadscha'), purple, green or colourless ('white'). Generally the more intense (or saturated) and even the colour, the more valuable the stone. Stones should not show too many dark regions (too much exctintion of light). Ruby is a variation of corundum, different only in the presence of chromium. The brilliant red lustre generates an intense 'traffic light' radiance, making rubies appear larger than than life. Sapphires may also be brown, grey or black, but the absence of colour makes these unsuitable for jewellery. It is not uncommon for sapphires to exhibit two or more colours (termed dichroism or pleochroism). Some sapphires show a different colour in a different light and are hence called colour change sapphires. Less coloured than cut stones, round star sapphires and star rubies boast 6 or even 12 well formed rays of light.
Sapphires are primarily sold according to carat weight, where 1 carat = 0.2 grams. Sapphires and rubies are a little heavier (more dense) than diamonds with a specific gravity of around 4.0 as opposed to 3.52. This means that a 1 carat diamond will be slightly bigger in size than a 1 carat sapphire or ruby.
Although all the shapes one sees in diamond cutting can be used to cut sapphires, stones one carat or larger tend to be cut either in an oval or cushion shape (a cushion being rectangular with rounded corners). Essentially any cut stone has three parts: a crown (the piece you see when the stone is set), a girdle (not seen, the slim middle part of a stone) and a pavilion (the pointed end of the stone which is also not seen). It is important that the crown and pavilion are well proportioned to reflect the maximum amount of light and that a cut stone exhibits good symmetry and is not off centre.
The clarity of a sapphire relates to freedom from external marks on the stone's surface and internal inclusions. When these are not visible to the unaided eye, a stone is said to be eye clean. Unlike diamonds, sapphires and rubies tend to be more variable in terms of clarity. However, this can help prove that a sapphire is natural and assist in confirming the country of origin. The overall transparency of a stone is therefore an important attribute. Stones with good colour saturation will tolerate more inclusions. Stones should not have badly worn or abraded facets. Internally True Sapphires aims to use sapphires based on the Gemological Institute of America's (GIA) very slightly included (VS) or slightly included (SI) standard under its type II grading for coloured stones. Please note clarity is not included in any certificate supplied. Our diamonds are Asian and .
Sapphires can be found in many countries including Kashmir, China, Colombia, Malawi, Nigeria, the Kanchanburi region in Thailand, Vietnam, Kenya, the Pailin river in Cambodia, Australia and Tanzania. True Sapphires principally sources fine blues and pinks from Sri Lanka (formerly Ceylon) and Madagascar.
Next to cutting, heat treatment is a skilled craft which has been used for centuries and is an industry wide accepted way of permanently enhancing the colour and clarity of natural sapphires and rubies. It is quite rare for sapphires or rubies not to be treated in this way. Unless True Sapphires clearly states to the contrary, you must always assume that a stone has been heat treated. True Sapphires rejects all other forms of treatment including chemical enhancement, diffusion, oiling, dyeing, irradiation and filling. Our offering of a laboratory Sapphire Report will independently confirm the authenticity of our sapphires and our full disclosure to you.
Because sapphires and rubies are very hard wearing, their toughness means they can be easily cleaned. In the first instance, they can be polished with a lint free cloth after wearing or alternatively washed in lukewarm soapy water using a mild liquid detergent before rinsing off in lukewarm water. If your sapphire or ruby jewellery hasn't been cleaned for a long time, it's probably best to get it professionally cleaned using a steam cleaner or ultrasonic bath with a cleaning solution. Ultrasonics are high frequency sound waves which shake off dirt by vibration.
Other care tips include avoiding activities which risk impact, shock, chemicals or heat. Remember gold is relatively soft. Although sapphires and rubies are resistant to chemicals, it's a good idea to avoid exposing them to cosmetics such as perfume, nail varnish or hairspray. Don't remove jewellery by pulling at the stones but do occasionally check for loose stones by lightly shaking or tapping the jewellery and listening for any rattle. Loose stones should have their settings adjusted. To avoid metal scratching, always store jewellery in its original case, soft padded pouch or a proper jewellery
box and never against another piece of jewellery. Finally it's not a good idea to remove jewellery when standing at a sink in case it disappears down the drain!
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