To try to help you out when purchasing your Sapphire Rings, Sapphire Engagement Rings and Eternity Rings, Sappphire Earrings, and all other Sapphire Jewellery you may be interested in, we have tried to put together some useful information, hopefully easing the selection process.
As when purchasing all gemstones and gemstone jewellery, there usually has to be some 'trade offs' unless your have a 'open-ended' budget. Usually it is simply a matter of finding a size and colour of Sapphire that meets your budget.
The overall grade of a Sapphire gemstone is determined by looking at Hue, Tone, Color-Purity, Clarity, Transparency and Cut. Taking all this into account and following gemmological industry standards supplied by such as EGL (European Gemological Society) and GIA (Gemological Institute of America).
Sapphires are graded as follows: Overall grade scores: Poor, Fair, Good, Very Good, Exceptional (Best).
Make up of a Sapphire
Sapphire is a form of Aluminium Oxide known as Corundum. Pure Corundum is in fact clear, and Blue Corundum, or Sapphire, is made up of Corundum (Al2O3), and Iron & Titianium impurities (Fe2+ & Ti4+), which are responsible for the Blue colouration.
Chemical Properties of Sapphire:
Chemical Formula: AL203+ Fe2+ Ti4+
Crystal Habot: Massive and granular.
Crystal Sytem: Trigonal.
Moh's Scale Hardness: 9.0.
Specific Gravity: 3.95 - 4.0.
Index of Refraction: 1.760 - 1.722.
Melting Point: 2030 - 2050 degrees centigrade.
Corundum is very hard, having a hardness of 9 on Mohs' scale, compared with 10 for diamond, and 8 for topaz. Hardness is generally a desirable feature is gemstones.
Ilmenite is not isomorphous with aluminium oxide. Isomorphous means being able to replace the host mineral within its crystal structure. Instead ilmenite is present as a microscopic inclusion, in the form of colloidal particles.
This colloidal nature may be responsible for other optical effects such as "silk", asterism, and colour banding.
When buying your Sapphires and Sapphire Jewellery, you must first consider the combination of Sapphire colour, clarity, weight and cut.
Colour of a Sapphire
Pure corundum is colourless, often called white, and although quite rare, tends not to be valuable because it does not have much brilliance. Colours, as in many gemstones, are caused by small amounts of impurity, usually metallic oxides. This is a case where impurity is desirable. Sapphires are identical in every way to a ruby, except for colour. Chromic oxide causes brilliant red colouring in corundum, thereby producing rubies. Ferric oxide causes yellow colouration, titanium oxide produces vivid blue. Found in a wide variety of colours – the main true colour that we are all familiar with is the Blue Sapphire. Sapphire can also be colourless. However, Sapphires are also available in pink, yellow, green and purple. These Sapphires are aptly named “Fancy Sapphires”. In addition there are other Sapphires, which are extremely rare and collectible termed as Padparadscha Sapphires.
Red corundum and most pink corundum is called ruby, blue corundum is called Sapphire, and other colours are also called Sapphire, usually with the colour specified as a prefix to the word Sapphire, for example, Yellow Sapphire. Brilliant Orange Sapphires are somtimes called Padparascha.
Colours of Blue Sapphires can range from a light blue to the darkest of blue (we call it black/blue). However, the middle of the road in the Sapphire gem group appears to be the most expensive (and the most sought after gem). Good rule of thumb to follow is that light colored and very dark coloured Sapphires will cost less and the mid range in colour Sapphires will cost more. Then again, never shop by price but by the size and the colour of Sapphire, which appeals to you the most. Many Sapphire buyers love a light coloured gem and many others prefer a midnight (almost black/blue in colour) Sapphire.
Padparadscha Sapphires - This Sapphire combines three colours – purple, pink and orange! A Sapphire displaying these colours is known as Padparadscha Sapphire and the cost of such a gem can costs thousands of pounds per carat!
Pink Sapphires – are a highly prized gem by many collector’s and consumers. Pink Sapphires can resemble that of a ruby (so be careful as you can’t go by colour – only by description). Again, Pink Sapphires can go from light pink to a very dark pink termed “hot pink”. Can't afford a Pink Sapphire? Search around for a Pink Topaz! They're reasonably priced (usually flawless) and come in a range from light pink to a "Hot Pink".
Yellow Sapphires – can be had at a very reasonable price, as they are found in extremely large crystal formations. They range in colour from a very light yellow (canary yellow) to a dark yellow. Looking for a Canary Yellow Diamond but, can't afford the price? Buy a Canary Yellow Sapphire, set it into a white gold setting (get the platinum look with a white gold setting!) and many will ask if the gem is a canary diamond! Keep the gem size down (under 2 carats), as Canary Yellow Diamonds of high quality are very expensive and anything over 2 carats might not be believable!
Green Sapphires – Another bargain hunter’s find is the Green Sapphire as they the least desirable of all Sapphires and range in colour from a very light green (like Peridot) to that of the darkest green.
Purple Sapphires - Of all the Sapphires, Purple Sapphires stand out as what we term a “middle of the road gem” with a great price and a nice colour range.
Star Sapphires – This is a gem you either like so much you buy every one you can find or this gem is just not your 'cup of tea'. They come in various shades of blue. The outstanding feature of this gem is the six or twelve ray star effect, which seems to dazzle it buyers. This gem is not that expensive and can be had for less then many of the Sapphires in the group mentioned above. The star is formed by inclusions that seem to float across the surface of the gemstones when moved.
Colour Change Sapphires – For those who love the colour change effect of Alexandrite or Tanzanite but don’t like the price. A colour change Sapphire is your best buy! The gem will change colour in various lighting, known as 'pleochroism'.
Cornflower Blue - Although Sapphire can be almost any colour, blue is the colour normally associated with it. Cornflower blue is frequently quoted as the best and most desirable colour for Sapphire. We would not argue with this. Colour is, in our opinion, the most important property for any gemstone.
Ceylon Blue - The term Ceylon Sapphire is frequently used to denote pale to medium Sapphires. Unless the stone is known to originate from Sri Lanka, as it is now called, such Sapphire should accurately be called "Ceylon-type" Sapphire.
Australian Blue - Currently most Dark Sapphires come from Australia, and the term "Australian Sapphire" is often used to denote dark coloured Sapphires, in a similar way to the term "Ceylon Sapphire" for lighter stones.
Ultimately which is "best" is a subjective matter, and personal preference is important. Our usual advice to potential customers is to buy whichever colour of Sapphire they personally find the most attractive. Buy what you like, using your own judgment, rather than allowing yourself to be a slave to fashion and buying what you think will impress other people.
Clarity of a Sapphire
Blue Sapphires tend to have more inclusions than most Fancy Colour Sapphires. Gemologists use the term "inclusion" to define characteristics found inside a stone. Inclusions are often used as an indication that the gemstone is of natural origin. A "blemish" is a characteristic that affects the stone's surface.
Sapphire Clarity Grades
- VVS - Very, very slightly included - minor inclusions that can be seen under 10x magnification, but invisible to the naked eye. No effect on appearance.
- VS - Very slightly included - noticeable inclusions unlikely to be visible to the unaided eye, but easy to see under 10x magnification. Little to no effect on brilliance.
- SI1 - Slightly included - large or numerous inclusions that can be easily seen under 10x magnification. These inclusions are apparent/somewhat apparent with the naked eye. Slight effect on appearance, little to no effect on brilliance.
- SI2 - Slightly included - obvious inclusions that can be easily seen under 10x magnification. Slight effect on appearance and brilliance.
- I1 - Obvious inclusions - significant effect on appearance, brilliance and transparency.
- I2 - Prominent inclusions - significant effect on appearance, brilliance and transparency.
- I3 - Numerous and prominent inclusions - severe effect on appearance, brilliance and transparency.
- Crystals - solid inclusions of various shapes and sizes. Extremely small crystals are referred to as pinpoints or grains.
- Silk - fine fibers of titanium dioxide (rutile) or other minerals that resemble the look of silk. Well-formed silk indicates that the Sapphire underwent no heat-treatment and is of natural origin. Silk is a preferred inclusion in sapphires.
- Needles - long, thin inclusions of either crystals, or tubes filled with gas or liquid (growth tubes).
- Cacks - feather-like inclusions also known as fractures or fissures.
- Parting - breakage along a plane of weakness.
- Twinning - two crystals grown out of one another or next to each other.
- Halos - circular fractures surrounding a crystal.
- Fingerprints - common in Sapphire, these inclusions look like human fingerprint outlines.
- Colour zoning - uneven colour distribution in the Sapphire.
- Cavities - holes extending into the Sapphire from the surface.
- Chips - broken off pieces along the girdle or on the culet of the Sapphire.
Sapphire Surface Blemishes
- Scratches - lines scraped on a gemstone.
- Pits - tiny holes on the stone's surface.
- Nicks - broken parts of a stone's girdle or facet.
- Abrasions - rough scrapings along the stone's facet edges.
- Transparency of a Sapphire
The degree of visibility through a Sapphire is known as its transparency. It is an often-overlooked characteristic when discussing sapphires.
Transparency is designated as follows:
- Transparent - objects look clear and distinct through the stone. These Sapphires usually have excellent brilliance despite any inclusions they may have.
- Semitransparent - objects look slightly hazy or blurry through the stone.
- Translucent - objects are difficult to see through the sapphire. Light can pass through, but it is somewhat diffused.
- Semi-translucent or semi-opaque - a small fraction of light passes through the stone.
- Opaque - almost no light passes through the stone.
The brilliance of a stone can be almost as important as its actually hue. A stone which is relatively free of inclusions will transmit more light, and therefore appear more brilliant. Attention to detail when cutting the stone can help the brilliance of any gemstone. It is well known that accurate proportions are important for diamonds, but less well known that it is also important for coloured stones also.
Cut of a Sapphire
The best Sapphire cuts offer a depth/width ratio higher than comparable diamond cuts. Expect a depth percentage of 65% to 80% for good quality Sapphires (the depth percentage is depth/width). Stones that are too deep will look smaller than expected but they will show off more colour than they would if they were cut to normal proportions. Deep-cut stones also preserve weight, increasing the cost of the stone without the expected increase in the size of the crown (top portion of the gem). Stones that are too shallow will look big for their weight and appear lighter in colour than deeper-cut stones.
Being an extremely hard gemstone that is very well-suited to jewellery purposes, Sapphires are cut into almost all of the known gemstone cuts, with Rounds, Cushion, Emerald, Pear and Oval cuts being particularly popular.
Good quality Sapphires also have good symmetry when viewed in profile - reflecting the light evenly.
Where is Sapphire Found?
Originally, the best Sapphires and rubies came from Burma, where they are believed to have been mined possibly from prehistoric times. Certainly they appear to have been worked during the times of Marco Polo.
Kashmir is another source of very fine Sapphires, famous for its cornflower blue stones. Thailand, previously called Siam, is an important source of attractive sapphire.
Whilst today's main sources of Sapphire are Africa, Australia, Myanmar (Burma), Sri Lanka (Ceylon), Thailand and the United States (Montana, North Carolina), there are also known Sapphire deposits in Brazil, Cambodia, India, Madagascar, Tanzania and Vietnam.
The highest quality and most desirable Sapphires are those that originate in India, Myanmar (Burma), and Sri Lanka (Ceylon). Sapphires from India and Myanmar (Burma), are highly prized for their pure blue colours and stones from these regions are priced accordingly, often at collectors prices, particularly if there is documentation available to prove the origin of the Sapphire. Sri Lankan (Ceylon) Sapphires are sought after for both their delightful pastel blue and fancy colored variations..
Almost all Sapphires found on the market today have been heat-treated in order to intensify colour and remove “silk” - the small inclusions present in most natural Sapphires. This method of treatment is considered permanent and colour should not fade over time, and therefore is universally accepted
The price range of Sapphires is very large, ranging from under £1 per carat to many thousands of pounds per carat, depending primarily on colour, but also on brilliance, which is affected by clarity and cutting.
As well as being used in virtually all types and designs of jewellery, other uses for corundum, because of its hardness, include its use as watch bearings, watch glasses, and as an abrasive.
Sapphire jewellery can be cleaned using hot soapy water, or detergent, rinse thoroughly afterwards as detergents can cause dermatitis and allergic reactions. Enzyme cleaners should be avoided for the same reasons. Brushing with an old tooth brush to remove dirt and grease will also help. Cleaning agents containing chlorine may have a detrimental effect on low carat gold alloys, so are best avoided.
Personal Preference (Love or Money?)
Whatever colour happens to be the most popular or most expensive, this does not alter our general advice to select gemstones which appeal to you personally. If the sapphire you like best is only half the price of another, trust your own judgment, go for the stone you prefer.
Of course, most of the time you will find that you like the most expensive stones best, in which case you may need to balance your budget against your emotions, but because jewellery is an infrequent purchase, we believe it is better to err on the generous side. Out of two stones competing for your attention, you will almost always feel happier in the long term when you buy the one you like best, even if initially there is a little anxiety or pain about parting with the cash!
Our Last Word….,
Here at Nuttalls of Chester Ltd, we strongly suggest you buy your sapphires carefully. Expect to pay more for larger size gems and remember that the ideal Sapphire should be relatively clear from fractures and inclusions. At the end of the day, "beauty is in the eye of the beholder'". So choose the colour you want, not what you are led to believe you want!
Whichever colour, size or shape of Sapphire you choose, be sure to wear it and ENJOY!
Thank you for reading this article - we sincerly hope it helps in some way...,
Why not view our extensive range of High Quality Sapphire Jewellery, including Sapphire Rings, Sapphire Engagement Rings, Sapphire Eternity Rings, Sapphire Earrings, Sapphire Pendants, Sapphire Necklaces, Sapphire Bracelets, Sapphire Brooch, and much, much more!