this is a guide for those that are looking to purchase a sapphire be it unset or set into jewellery.the 4 c's as withany gemstone apply
COLOUR-with australian sapphires you CAN GET THEM IN ANY COLOUR,and the variance on the shade of colour depends on the secondary colour in the cross table. e.g. blue on green means that the colour on table is blue and the colour in the cross table is green.the depth of the blue on table is governed by the depth of green in the cross table-dark green in the cross table will give you a VERY DARK inky blue -pale green to yellow in the cross table will give you a bright lively blue. the ideal blue IF you can get it is blue with a white cross table,very hard to find these days.
CLARITY- This refers to any internal inclusions occuring naturally in the sapphire. out here we facet for quality and try to the best of our ability for a flawless stone. the rare occasion where the inclusions are left in is when you get an exeptional colour where the inclusion/s do not detract from the overall appeal of the stone. NOTE - withsapphires and rubies -yes they are one and the same- if the stone looks cloudy or opaque or "sugary" it is not a 1st or second grade stone, this is generally in the case of opaque and sugary looking stones what is graded as corrundum- which is not gem quality stone. Many untreated sapphires may have a slight tinge of milkyness to it or possibly bands of "bronze" though it . Whilst not a top grade stone they can have some very unique characteristics that make them collectors pieces.
The main thing to watch for is the Sugaryness" and the pronounced opaquness of the stone. When compared to a first gade gem quality sapphire it's like chalk and cheese.
CUT- the refers to the type of cut used to get the best out of a sapphire aximizing the finished weight whilst keeping the quality of the sapphire to its absolute best. there are some of the best commercial cutters out here on the central qld. gemfields and NO they are NOT OVERPRICED! It can take anywhere fron one hour to five hours to facet a sapphire to get the best out of the material provided. prices are from 30 percarat ON THE FINISHED WEIGHT to 55 per carat which usually relates to an oval,barrion, or freeform faceted stone as these are the time consuming ones. Compare the price to what your mechanic charges per hour and you will see that the faceting prices out here are very reasonable.
CARAT- just like diamonds, the bigger the stone the more per carat it is worth and the rarer the colour the price per carat goes up accordingly.I have on auction at the moment a 3.90 carat golden yellow/orange freeform sapphire untreated with 2 natural inclusions which lokks eye cleanon table.this if akinen to a valuer would be worth-depending if the valuer knows anything about sapphires other than"i thought sapphires were only blue!" , around the $1200-$1400 per carat! nice to make an offer but try replacing the bugger with another one- they just aren't there any more in that size or colour.
BEWARE--- THE NICE BRIGHT REDS ORANGES PINKS AND THE "COBALT BLUES" These should be purchased with caution as there is a tremendous amount of BERRILLIUM TREATED SAPPHIRE floating around out there. I got so sick of answering the same questions day in amd day out if my stones were natural or had been berrilium treated that I put up a NO ARTIFICIAL COLOURS FLAVOURS OR PRESERVATIVES ADDED sign up in the shop. berrillum treatment alters the chemical composition of the stone.It is no longer classified as a sapphire in my opinion if it no longer has the identical chemical properies of a natural sapphire.
I am a semi retired jeweller by trade and by no means do I have a gemology degree but i think that if your going to purchase a sapphire-go for the real thing-even come out and dig it up your self-you'll find out just how hard it is to find one-check its authenticity check its cut- there are alot of overseas cut stone even here on the gemfields-locally cut stones are easy to see -most of your overseas cuts have shallow tables and deep curved pavillions(bottoms), and are generally easy to pick in the round brilliant ,oval or trilliant cut because the proportions are not balanced. The proportions as an example for a round brilliant locally faceted on the gemfields-in layman terms the top of the stone has a flat in the centre this should in a standard commercial cut be on average one third of the diameter of the stone and no more tha 40%. when you view the stone side ways you have the crown hich is the top section of the stone , the girdle which is the edge of thestone and then you have the pavillion which is the bottom section of the stone . Ideal proportions are- table -one third of the overall depth of the stone -pavillion- two thirds of the overall deoth of the stone. the girdle or edge of the stone should be in proportion to the overall stone -not "so thin you can cut yourself on" and not so thick that you cuold "drive a horse and cart over".
I would encourage people to ask questions -that is sensible ones so that you do get the best for your money.I am totally new to ebay and as I plodded my way through the jewellery/gemstones etc I found a lot of good things but oh so much costume junk when searching for "goldsapphire" jewellery . maybe there should be a section separate from the costume jewellery which defines the real stuff from the costume jewellery