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New to coloured gemstone buying? Read this first!

Discussion in 'Colored Gemstones' started by LD, Apr 15, 2012.

  1. chrono
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    by chrono » Aug 24, 2012
    Hard stones are not necessarily tough stones. There is often the misconception that a high MOH score also means that the stone is able to resist blows as well as abrasion. Toughness is a measure of how much impact energy can be applied to weak points such as sharp edges of facets and corners of a gemstone without breaking. All faceted gemstones are brittle to some degree but other varieties will chip excessively even with proper care and set in a protective style setting.

    Cleavage is a weakness due to the crystalline structure of the gem. It can have more than one cleavage plane which means that when enough pressure is applied in the right location, the stone will split into two (or more) pieces. The orientation and location of the cleavage can incrrease the possibility of chipping along some edges of the stone, regardless of its hardness.

    Corundum: No noticeable cleavage, is very tough and very hard.
    Chrysoberyl: No noticeable cleavage, is reasonably tough and very hard.
    Spinel: No noticeable cleavage, is very tough and very hard.

    The next few are not recomended for everyday wear rings with explanation to follow:

    Topaz: Has perfect basal cleavage, meaning it is likely to be damaged by a blow or when dropped on a hard surface. Thus it is best suited for an occasional wear ring.
    Garnet: Tough enough for use in rings but does not resist wear as well as those mentioned above. An exception is to be made for demantoid garnets which is quite low on the MOH scale.
    Zircon: Rather brittle and the artificially whitened zircons are especially prone to breakage when worn in rings.
    Beryl: Rather brittle so facet wear will show around the table area more easily.
    Tourmaline: Rather brittle and thus more likely to chip and show facet wear. Its toughess is rated as fair to poor.
    Kunzite: Pronounced cleavage so it is best not to set in a ring.
    Quartz: No pronouced cleavage and is fairly tough. In time, the facet edges will dull from friction with common dust (which is usually powdered quartz). Very little risk of fracture unless (like every other stone and diamond) the impact is severe.
    Stone with quartz basis like chalcedony, carnelian, agate, jasper and etc are tougher than clear crystallized quartz due to its internal structure. These type of waxy stones are very wearable.
    Jade: An exceedingly tough material and fairly hard, thus it is extremely wearable in almost every fashion. The reason for this toughness is due to its interlocking fibrous internal structure. This includes both jadeite and nephrite.

    Peridot: Rather soft for ring use and also prone to facet wear and chipping.
    Turquoise: Fairly tough material but is porous enough to absorb oil and other liquids which might affect its colour.
    Moonstone: Pronounced cleavage and lack of hardness means it is not a good candidate for a ring setting but as most are rather inexpensive, it may not matter.
    Opal: Soft, brittle and cracks easily. Will require repolishing over time if worn in a ring.
     
    USCgal likes this.
  2. BenL
    Rough_Rock

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    by BenL » Aug 28, 2012
    This is great information for a newbie like me. Thanks!
     
  3. Brillance
    Rough_Rock

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    by Brillance » Nov 2, 2012
    Hello LD, appreciate the article, give us newbies very good insight and honest views into this dazzling world of colored stones..

    A purple sapphire ring and a blue tarzanite ring caught my eye today and as I am totally clueless about colored stones, I asked for the cert for the sapphire (the tarzanite doesn't have one). The cert says flux fingerprints, crystals...which are the inclusions in the stone. The stone also has a very beautiful deep color which like what you said may be pre-heated. The cert did indicate that "heating may be possible".

    The shop says having flux finger prints and crystals are normal for natural stones. Could you advise if this is so and now that likely the stone has been heated before, the price shouldn't be so expensive. The listed price is about Singapore $18,000 and after some big discounts which are very common here in our country, the selling is at $6600 which I still think seems very expensive but if this is like a piece of heirloom, I may just purchase it. The problem is that I don't know if this stone is a good one.

    Btw, the tarzanite is 2.6C and the purple sapphire is 2.4C.

    Looking forward to your kind advise.. And thank you..

    Warmest,
     
  4. chrono
    Super_Ideal_Rock

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    by chrono » Nov 2, 2012
    Brilliance,
    Please start a new topic with your questions so that it won't be burried here. I can answer some of them right away in your new thread.
     
    


    


  5. Brillance
    Rough_Rock

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    by Brillance » Nov 3, 2012
    Thanks Chrono, I have posted my question on a new thread and got my response, many thanks for highlighting ...
     
  6. chicago4323
    Rough_Rock

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    by chicago4323 » Dec 18, 2012
    LD > This was very helpful! Thank you so much!
     
  7. meenakshi
    Rough_Rock

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    by meenakshi » Dec 28, 2012
    Amazing Post!
     
  8. innerkitten
    Ideal_Rock

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  9. meredeth11
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    by meredeth11 » Apr 15, 2013
    Very useful post,thank you very much :twirl:
     
  10. rerayrod
    Rough_Rock

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    by rerayrod » May 1, 2013
    okay this may sound a bit embarrassing, but i just joined and don't know how to post a new thread or new topic. PLzz help! :confused:
     
    


    


  11. chrono
    Super_Ideal_Rock

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    by chrono » May 2, 2013
    When you are on the main "Coloured Stones" webpage, right underneath to the far left is a small button "New Topic". Just click on it and you are good to go.
     
  12. styringca
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    by styringca » May 7, 2013
    OK,Thanks for your tips.
     
  13. colorchange
    Shiny_Rock
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    by colorchange » Jun 20, 2013
    This is a very good start, but it’s missing a huge leg on origin and a small leg on fluorescence.
    In most gemstones (rubies, sapphires and fancy sapphires, emeralds, chrysoberyls and even spinels), origin matters.

    I had a complete article on that on my (now offline, but will be back) website, and I think I’ll need to volunteer to help, as it affects value so much, and you see so many sellers claiming ridiculous origins for their gems (sometimes, even often, in good faith).

    These days, it looks like every padparadsha (or orangy sapphire) is from Sri Lanka and every ruby is either from Burma or Mozambique/Tanzania... I wonder where all the Vietnam, Ceylon and Madagascar rubies are gone, not talking of Tajik and more un-usual locations (actually, I don’t really wonder, I do have rubies from all over the world, but often bought by a vendor alleging something else)

    And regarding fluorescence, it changes so much the way a gem looks... fluorescence is sometimes one of the main reason an origin is sought after.
     
  14. LD
    Ideal_Rock

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    by LD » Jun 24, 2013
    Thank you for your post.

    This thread was started to help people who have never bought a coloured stone before and give them the basics of where to start. In my opinion, understanding fluorescence does NOT help a new buyer when purchasing online. Although it's a fascinating subject, there are a plethora of threads on this board that can be linked to that will help people understand it but fluorescence typically concerns people who buy diamonds far less than those who buy coloured stones. The average first time buyer does not need this knowledge and it would assume they have also seen and been able to compare fluor in a large range of gemstones.

    In terms of origin - it would be a waste of time writing anything because there are good and bad stones from every location. Seeing the word "Burma" does NOT denote that the stone is good or warrants a higher price tag. This thread was written so that the uninitiated could evaluate a stone as a stand-alone or when comparing - by looking at colour, clarity, price etc. At the end of the day that speaks volumes. You have admitted that when buying most of your stones they have turned out to be from a different location than advertised so that says it all really! Buyers should be wary of any advertised location and should simply buy the stone they love best. IF there's a price increase because of location then the savvy buyer will make the purchase dependent on an origin report from a laboratory (if it can be determined by testing - sometimes it can't).

    If you would like to write a thread on origin please do so but as you're in the trade anything regarding pricing may be contentious so I suggest you speak with the administrators before publishing. Please understand I wrote this thread originally in an hour and it was aimed at helping a number of new posters who were on the board at that time all asking similar questions. It is not meant as a full learning tool - just a starting point.
     
  15. lovefordiamonds
    Shiny_Rock

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    by lovefordiamonds » Jun 25, 2013
    Thanks for the post!! I now know where to start! hehe :D
     
    


    


  16. colorchange
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    by colorchange » Jul 8, 2013
    >>> You have admitted that when buying most of your stones they have turned out to be from a different location than advertised

    Of course not. Just that I intentionally bought many Madagascar fancy sapphires from sellers pretending them to be Ceylon !
    Now of course I’m not 100% reliable, and funnily I bought there a lot of violet sapphires, looking great (fluorescence), but weird to my eyes. Turned out to be Pakistani. Of course that was when Pakistani traded below Ceylon (it’s now the opposite).

    >>> Seeing the word "Burma" does NOT denote that the stone is good or warrants a higher price tag.

    Unfortunately these days, it does warrant a larger price tag for the same look. Just like a Burmese ruby might look like a Vietnamese one, but have a very different value. Even if it’s looking quite bad.

    >>> If you would like to write a thread on origin please do so but as you're in the trade anything regarding pricing may be contentious so I suggest you speak with the administrators before publishing. Please understand I wrote this thread originally in an hour and it was aimed at helping a number of new posters who were on the board at that time all asking similar questions.

    It’s a great post and clearly will be very useful to many.
    You’re likely right that I should avoid such contentious subjects here.
     
  17. pregcurious
    Ideal_Rock

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  18. LD
    Ideal_Rock

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  19. JewelFreak
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    by JewelFreak » Aug 14, 2013
    Corundum (sapphire and ruby) treatment


    Chrono


    I'd like to start off with this article written by Richard Hughes on the treatment of rubies. It was written in 1997 but was too shocking to some groups to print. This article was later revised in 2002 to remove the term glass filling because this treatment is mainly for the purpose of fracture healing, not fracture filling.
    http://www.ruby-sapphire.com/foreign-affairs.htm

    Another slightly updated article by Richard Hughes
    http://www.ruby-sapphire.com/flux_healing_mong_hsu_ruby.htm

    Flux healing involves heating corundums with borax or other fluxes. These fluxes actually dissolve the surfaces, including the internal surfaces of cracks. The corundum within this molten material then re-deposits on the fracture surfaces, filling and healing the fractures shut. Undigested material cools into pockets of flux glass. Essentially this amounts to a microscopic deposition of synthetic ruby to heal the cracks closed.

    In the broadest sense, this is akin to the oiling of emerald – both treatments involve reduction of reflections from included cracks/fissures. Similar to placing an ice cube in water, a filled fracture is much less visible because the filler replaces air (RI = 1.00) with a substance that has an RI that more closely matches the gem itself (1.76–1.77). However, the flux healing of Mong Hsu rubies differs in three important respects:
    •The Mong Hsu ruby treatment is NOT a fracture filling, but a permanent healing of the fractures and fissures, with any filling merely a remnant of the process. In many respects, it is a welding of fractures, similar to the joining of two pieces of metal with heat and a flux to lower their melting point.
    •The Mong Hsu ruby treatment is permanent and irreversible. Unlike the oil in an oiled emerald, flux remnants will not drain out in the future, nor can they be removed. There is no way to have a stone revert back to the untreated state.
    •The Mong Hsu ruby treatment actually improves a stone’s durability, since the fractures are permanently healed shut.

    A 2010 research paper submitted by GIA which applies to all rubies, not just from Mozambique
    http://www.gia.edu/research-resourc...d_glass_filled_rubies_from_Mozambique_edu.pdf

    There are three types of flux treatment listed and it is important to understand their differences:
    FAPFH – Flux Assisted Partial Fissure Healing
    GFF – Glass Fissure Filled
    LGFF – Lead Glass Fissure Filled

    While FAPFH, LGFF and GFF stones all result in stones that have been “clarity enhanced”, the essential difference between the three types of treatment is that the fissures in FAPFH treated material are “healed” closed by synthesis while fissures in either LGFF or GFF are not, i.e., FAPFH fissures are stable (once any surface glass has been removed by HF) whereas LGFF and GFF treated fractures unstable (they will break down and become obviously visible). In severe cases of LGFF treated rubies the LMHC laboratories developed severely worded
    descriptions; these are “ruby with glass” and “ruby‐glass composite”.

    How is this done, you say?
    The ruby is heated to temperatures that may reach as high as 1850°C in the presence of a molten flux. At these temperatures the surfaces of the ruby (alumina) in contact with the flux will slowly dissolve into the flux. During the gradual cool down period the alumina comes out of the flux and crystallizes on the nearest available surfaces. These surfaces may be those of the crucible in which the process is taking place or on the rubies being treated. If crystallization takes place on the rubies, this may be on the outer surfaces (facets) of the stones or on the inner surfaces of any fissures that may be present. If the crystallization is on the inside of fissures, the build‐up of synthetic material will cause the fissures to gradually close or “partially heal” (Figure 2). These partially healed fissures have the appearance of intricate networks of fine tubules contained in undulating planes within the stone. The material that can be observed within these planes is mostly composed of a glass; the transparent spaces within the planes are where the fissures have been partially healed with synthetic corundum.


    Re: Ruby Treatment


    Then there is glass filled rubies which is not to be confused with flux healed rubies.
    http://lgdl.gia.edu/pdfs/gemsandgemology/articles/Sp06-G&G-article-on-lead-glass–filled-rubies.pdf

    The first step involves preforming the material to remove any matrix or obvious impurities. The second step is referred to as “warming,” that is, heating the stone to moderate temperatures (reportedly 900–1,400°C). Often used as a first step in standard heat treatment, ”warming” removes potential impurities from the fractures and may improve the color. The third step involves mixing the stone with powders that are composed primarily of lead and silica but may also contain sodium, calcium, potassium, and metal oxides such as copper or bismuth. This mixture is then heated again, reportedly to approximately 900°C, fusing the powders into a glass that penetrates the fractures in the stone.

    Lead glass filling can be done on both flux healed rubies and those that have not been healed (exposed to the extremely high temperatures required to heal the fissures closed).

    Lead glass / composite ruby
    http://www.aglgemlab.com/news/Composite Ruby.pdf

    These types of treatments allows different levels of ruby material to enter the market to fit their respective niche. High-temperature heat treatment and healing of fractures brought Mong Hsu ruby to the market years ago for what was at the time a very low price. Clarity enhancement with high-lead-content glass has brought ruby and pink sapphire to the market for even lower prices. Depending on the original material, some are very fine in quality (face up).
    Last edited by Chrono on 11 May 2012 11:25, edited 1 time in total.


    There is a relatively new ruby treatment developed in Thailand that is a modification of the lead glass or composite ruby treatment. The ruby is treated using various chemicals or fluxing agents similar to the more traditional heating of ruby that results in fissure healing and heating residues. During AGL’s investigations, it became evident that in some samples fissure healing was taking place, whereas in others there was less healing taking place but open fissures were still being in-filled with a glasslike material however no lead or bismuth was detected as would be expected of a typical Composite Ruby. AGL has determined it will classify this treatment as glass-filled and not composite ruby.
    http://www.aglgemlab.com/news/New Ruby Treatment-Frequently asked questions-May 2010-AGL.pdf

    Traditional heating of rubies

    As part of the heating process for rubies, it is common practice to coat the stones in a variety of fluxing agents. As the temperature increases, these fluxing agents melt, partially dissolve the ruby’s surface and facilitate in the healing of fissures, effectively sealing and reducing the appearance of the fissures and improving the general durability of the stone. The use of fluxing agents during the heating process results in a combination of features or materials being deposited and remaining along the newly healed fissures. The previously open fissures are replaced by planes consisting of re-grown ruby (synthetic), solidified vitreous melt (glass) and voids (empty bubbles). The relative amount of these three parts depends on many factors.


    I think Arkteia asked about fluorescence in rubies so I thought she might like to read this:
    http://www.ruby-sapphire.com/heat_seeker_uv_fluorescence.htm
    Doing this test requires a good bit of gemological knowledge though and just because a ruby might be inert, that does not mean it is unheated. The stone also has to be clean before testing because soap and other chemicals can produce chalky fluorescence. This test is not definitive and should be ONE of the testing methods used together with a complete gemological examination in a fully equipped lab.


    Sapphires or corundum undergo various treatments ranging from heat only (sometimes this is referred to as low heat although the temperature isn't low at all), diffusion (heated to almost melting point and minerals are added to alter the original colour), clarity enhancement and irradiation.

    Diffusion

    Although this article was written in 2003, it still provides useful information about diffusion.
    http://lgdl.gia.edu/pdfs/su03a1.pdf

    Beryllium diffusion is done to improve all colours of corundum, turning almost colourless or pale corundum into stunning yellow and orange sapphires, pink sapphire into a “padparadscha” appearance or a vivid orange, as well as the conversion of bluish rubies to a fine red color. It also can reduce the amount of blue in dark blue sapphires, rendering them a more attractive colour. Not all sapphires treated with beryllium show an intense colour though, so a bright vivid coloured sapphire isn't the only suspect for diffusion.

    There are many types of diffusion, begining with titanium where it produced a blue layer under the surface, called “surface diffusion” by some gemologists. If you cut into the stone, you can see this effect easily, where it shows the effect of the colour only on the outer rim. With Be diffusion, the induced colour layer penetrates deep into the stone, giving it a full and even colouration. Beryllium is introduced into corundum by adding chrysoberyl to the crucibles in which the stones are heated. As you can see in the many pictures in the article, sapphires from different locales in the world have been subjected to diffusion, not just Songea sapphires.

    Be diffused stones can be identified by mass spectroscopy like SIMS analysis, LIBS and LA-ICP-MS but these technique is expensive and time consuming. Usually, the presence of certain inclusions is sufficient to prove a particular stone has not been exposed to the high heat temperatures required for diffusions and therefore could not be diffused.

    1. CO2 Inclusions – Internal “voids” that contain water and a bubble of carbon dioxide (CO2) are quite common in sapphires from some localities, particularly Sri Lanka. Because CO2 expands when heated, these inclusions cannot survive the very high temperatures necessary for Be diffusion. Therefore, the presence of undamaged inclusions would prove that a stone has not been Be-diffusion treated.

    2. Internal voids filled with other liquids will also not survive high-temperature heat treatment. The presence of undamaged liquid-filled voids of any kind proves that no Be treatment has occurred.

    3. Included Crystals – The presence of undamaged zircon crystals in a sapphire is a good indication that Be diffusion treatment has not taken place. It is unlikely that any crystalline inclusion could survive the temperatures required for Be diffusion without being significantly
    altered. Therefore, the presence of transparent, angular, or rounded solid grains of any mineral would be an excellent indication that Be diffusion has not taken place.

    4. Rutile Needles – Needle-like inclusions of rutile, often referred to as “silk,” are common in corundum from many localities. These needles usually survive the lower-temperature heat treatments that are performed on some sapphires. However, they typically do not survive the higher-temperature treatments to which most blue sapphires and rubies are subjected, including the very high temperatures necessary for Be-diffusion treatment. The presence of unaltered rutile needles means that a stone has not been exposed to this (or any other) high-temperature treatment.

    Diffused corundum is not affect by routine cleaning (steam and ultrasonic) and jewellery repair procedures. The treatment is stable and permanent. However, it is well known that the use of borax-containing chemicals (both fire coat and flux) contributes to moderate to severe surface etching of corundum. If etching due to exposure to borax-containing compounds is severe enough, the stone might
    have to be repolished.

    Transparent corundum is actually a common commodity. Only corundum in attractive colors and color saturation levels is rare. There are large deposits of sapphire that can produce large stones in unmarketable colors. Conventional heat treatment can improve only a very small percentage of such material. However, it appears that much, if not most, of this material can be Be diffused to produce
    attractive colours.


    Irradiation

    Some corundum (pale yellow, brownish and grayish sapphires) are sometimes irradiated to produce an attractive saturated golden yellow to orange yellow colouration. This type of treated sapphire is safe for wearing but the colour will fade over time. Irradiation is difficult to detect through lab testing and a "fade test" will take some time.

    A bit of an eye opener on how effective diffusion is at improving the appearance of sapphires. Note that not all diffused sapphires start out looking like the gravel posted below.
    http://www.palagems.com/gods_graves_sapphires.htm

    Really interesting (at least to me) chart showing how the labs define the levels of flux healing with pictures shown on Page 2.
    http://www.lmhc-gemology.org/pdfs/IS1_18012010.pdf


    Heating: What does it do and why

    A majority of sapphires and rubies are heated to change colours, intensity the saturation and also increase clarity. Those that come out of the ground looking great (done by Mother Nature herself) are less common and thus command higher pricing. Heating improves clarity by "removing" the opaque inclusions and also allowing chromophore-type elements, such as Ti (titanium) and Fe (iron) to become part of the corundum crystal and help colour the stone.

    Heating is essentially the oxidation of corundum impurites which are composed of rutile (TiO2), spinel (ideally MgAl2O4, but often "impure") and iron titanium oxides such as ilmenite (FeTiO3). Corundum's melting point (~2000 °C) is higher than most of its common inclusions. Thus, heating allows the solid inclusions to resorb or "melt" back into the corundum's crystal structure without melting the corundum. The reduction of Fe3+ to Fe2+ causes colour in a variety of sapphires to change. Stones that are too deeply blue may be lightened by the oxidation of Fe2+ to Fe3+. In some cases, heat treatment will improve the depth of color because heat causes dissolution of inclusions and diffusion of impurites (especially Ti from rutile inclusions) into the surrounding corundum. Because fine inclusions cause some stones to look cloudy, heat treatment that dissolves the inclusions may also improve the clarity of the stone.

    Fluid inclusions and fracture-type inclusions won't add to a stone during heat treatment, but these features can be annealed or healed to make them "disappear". Consequently, the clarity of the treated stone can increase dramatically.

    As you can see, not all the "gravel" were improved - some remained dark and blackish. Some that are overly dark are lightened in tone with heating, then diffused to alter the colour. Heating also improves the clarity by dissolving the inclusions. Fluid and fracture type inclusions will be "healed" and disappear as they melt back into the surrounding corundum.

    Oiling

    An increasing number of sapphires treated with oil are appearing in the marketplace. Oiling the stone is a way to fill surface fractures. This treatment enables gem dealers to sell a larger stone (at a higher price) because fractures that might otherwise have to be cut away are filled with oil. Oil fillers are not stable and will evaporate over time, leaving a less attractive stone with readily apparent fractures. This treatment is coming into use and is often not disclosed by the gem supplier.
    http://jcrs.com/JCRS_for_consumers/jewelry_information/colored_gems/sapphire.htm


    There are many pictures on Page 6 (figures 1 through 9) showing that some clarity enhanced rubies do not need to undergo high heat temperature heating. Silk in the form of fine intersecting needles both in isolated clusters and as part of hexagonal zones are often present, as well as crystals and negative crystals. None of these inclusions reveal any indications that they had been subject to heating, at least above 1300C. This "low heat" step is important to remove the impurities possibly present in the fissures that could create some problems when the glass is added. The heat treatment may also by itself improve the stone color. This “warming” can be conducted at different temperatures from 900C to 1400C depending on the ruby type. As 900C is not hot enough to melt some inclusions as rutile, many stones can still have an “unheated” aspect. But all stones are heated.

    Thank goodness the glass can be detected by some tell tale bubbles and coloured flash though!

    http://www.giathai.net/pdf/Ruby-Glass_Composites.pdf



    Unread post by Lee Little » 23 May 2012 08:47
    Excellent work Chrono.
    That combination of flux healed and glass filled is one to watch for now. I had not seen one, or at least I thought I hadn't. Just now I was ready to call a ruby I was looking at as a flux healed when I saw a tiny bubble. On closer exam it turned out to certainly have flux veils PLUS bubbles in glass. Previously when I saw flux veils and natural inclusions I thought I was done looking! Best regards, Lee


    Unread post by iLander » 23 May 2012 09:06
    I hope I'm not stepping on your toes, Chrono, just wondering if you saw this article about Winza rubies and heat treatment in the field, from the GRS.

    http://www.gemresearch.ch/news/Tanzania/Tanzania.htm

    It's not as informative as your articles, and hopefully I didn't duplicate one of your articles.


    Unread post by Chrono » 05 Oct 2012 07:45
    This is old news but I wanted to point out that just because the sapphire isn't neon in colour means it has not been diffused. The link below shows many pretty blue sapphires that have been diffused.
    http://www.gia.edu/research-resources/news-from-research/Be-diffused_blue_sapphire.pdf
    Lots of amazing research done on treatments for all types of gemstones!
    http://www.gia.edu/research-resources/news-from-research/index.html



    Update for new diffusion treatment of corundum. Do NOT assume that if your sapphire shows zoning, it is not diffused. That is no longer true with this new diffusion method.
    http://www.gemresearch.ch/news/2011-12-19_Alert/Alert.htm
    Snippet:

    A large number of diffusion-treated stones are detected in the laboratory. The diffusion-treatment includes the well-known method of adding Titanium in the surface. Some of the material has been additionally Beryllium-treated. The new aspect of this treatment is that the treaters obviously select already heat-treated sapphire with internal blue color-zoning. Than the stones are diffusion-treated and recut. This allows the stone to be enhanced by 1-2 color grades. When such stones are recut by the end consumer, the color becomes lighter mostly back to the color grade previously to the diffusion-treatment. GRS uses immersion and ED-XRF chemical testing and LIBS-testing to identify the new method. More details will follow later.

    Buyer be aware of using color-zoning in any heat-treated sapphire as a criteria to distinguish between diffusion-treated and non-diffusion-treated sapphires. Such stones may well be diffusion-treated. Furthermore, the blue edge effect may have been made less obvious by an additional Beryllium-treatment process. This would make the identification with the loupe even more difficult.
     
  20. dnilson
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    by dnilson » Sep 8, 2013
    In another post I was asking about an online vender named Gems NY www.gemsny.com They are reportedly selling wholesale to the public. Anyone know if this is true? They do seem to have some very nice stones at very good prices. Some come with GIA reports, but most only have UGL reports. I've never heard of UGL. Are they reputable? In the cases where the stone had both GIA and UGL, they were pretty much the same, except that UGL will include origin and specifics about treatments. I know that GIA WILL include origin if requested, but I've never seen any GIA reports on this site that state origin. Regardless, they do APPEAR to be legit. Could someone help me? I mean, who wouldn't want to buy wholesale if they could? Thanks in advance!
     
  21. chrono
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    by chrono » Sep 9, 2013
    If a vendor is selling to the public, that is considered retail, not wholesale, no matter how hard they insist it is wholesale. As for Gems NY, a quick search through PS will bring up different opinions / reviews about the vendor. GIA reports are accepted by everyone, UGL far less so and is not a lab report that is considered consistent or reliable compared to GIA. Origin isn't everything and only matters in a few select cases, although it affects pricing even on stones that are lacking in colour. Treatment matters and GIA does test for treatment and states as such on their reports.
     
  22. colorchange
    Shiny_Rock
    Trade

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    by colorchange » Sep 27, 2013
    I always wondered why the excellent code of ethics of the AGTA (http://www.agta.org/about/ethics.html) didn't include provision to ban the use of the term "wholesale price".
    (Incidentally, it doesn't mean much. Is wholesale the price I pay in Bangkok, the price I pay in Colombo or the price I sell to jewelleries in Europe ??? It's clearly not the same prices - else I wouldn't make a living)
     
  23. LtypeI
    Shiny_Rock
    Trade

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    by LtypeI » Nov 4, 2013
    Thanks so much to everyone who put so much great information here!
     
  24. mochiko42
    Ideal_Rock

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  25. LeaD
    Rough_Rock

    Messages:
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    by LeaD » Feb 5, 2014
    Great post LD.
    I wish I had come across it earlier...
    I also liked the video number 2 How to Distinguish Between Good and Bad Gemstone Faceting by John Dyer on the following page
    http://www.johndyergems.com/videotutorials.html
    It helped boost my confidence on being able to spot dubious cuts (not that difficult actually in many cases).
    Hope it might also help other newbies.
    Best
     
  26. minousbijoux
    Super_Ideal_Rock

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  27. LindaHogan
    Rough_Rock

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    by LindaHogan » Feb 24, 2014
    Hello ,

    this is absolutely wonderful post. So informative !
     
  28. LeaD
    Rough_Rock

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    by LeaD » Mar 3, 2014
    I just saw an interesting post on a topic "recutting a gem", which I believe might be of recurring interest. Especially for other newbies, who might well some time come across a nice but poorly cut gem, or with not their "dream cut" and ask themselves those questions. It certainly was informative for me.
    https://www.pricescope.com/community/threads/recutting-cs-from-emerald-cut-to-a-more-scintillating-cut.199129/

    I added a few older posts I found while digging that topic. No guaranties I might have not missed others as good or even better :wacko:
    https://www.pricescope.com/community/threads/cost-of-gem-recutting.137725/
    https://www.pricescope.com/wiki/colorgems/colorgems_cut

    Hope it might be of interest to others as well.
     
  29. FrekeChild
    Super_Ideal_Rock

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  30. ILoveGems14
    Rough_Rock

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    by ILoveGems14 » Jul 27, 2014
    Awesome post LD!!!! :appl: :appl: :appl:
     

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