How to Identify Neelam (Blue Sapphire)?

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    How to identify blue sapphire whether it is real or not ?


    In market both natural and synthetic blue sapphires are available. Separation of natural blue sapphire from synthetic by naked eye is nearly impossible, even gemologist fail at certain level to separate them visually. The natural sapphires that we get in market are mostly treated (heat & diffusion). It is again difficult to identify these treatments with naked eyes.

    First, never ever separate a blue sapphire from other blue gemstones only on the basis of shade, since blue sapphire comes in all shades of blue.

    There are basically 5 gemstones that appear (replicate) as blue sapphire. These are Synthetic Cubic Zirconia (a.k.a. C.Z, American Diamond), Iolite, Tanzanite, Benitoite and Man-made blue glass.

    Separation of Blue Sapphire from:

    1. Blue Synthetic Cubic Zirconia (C.Z.): Blue C.Z. is the most common substitute for Blue Sapphire. An experienced gemmologist or trader can easily separate Blue C.Z. from Blue Sapphire even by weighing these stones on hand; because if we take same volume of Blue Sapphire and Blue C.Z. then Blue C.Z. will be heavier as its specific gravity is more. Also, C.Z are often eye clean but sometimes have zirconium oxide “powder droplets” which can appear as rows of dots.
    2. Iolite: If Iolite is rotated from different direction it will show a shade of yellow which doesn’t appear in blue sapphire. So if your blue sapphire doesn’t show yellow shade then you can be certain that it is at least not Iolite. Note: Sometimes iron staining in blue sapphire can be the cause for yellow shade. So this is not conclusive evidence.
    3. Benitoite: Benitoite is a rare gemstone and it is less likely that you will encounter it. However, you can separate Benitoite with “doubling test”. When you look through facets of Benitoite towards culet, culet will appear as two. Even inclusions inside Benitoite will sometimes appear as two. This is a confirmatory test as there is only one natural blue stone with doubling effect.
    4. Tanzanite: Tanzanite shows three shades of blue when looked through dichroscope whereas blue sapphire will show only two shades of blue. You can also separate it with instrument called refractometer. Eye separation of tanzanite from blue sapphire is difficult. It requires certain instruments to get it separated.
    5. Man-made Blue Glass: Glass is a good simulant for all gemstones. All man-made glass has “gas bubble” inclusions which appears as round or oval or elongated. New people might find it difficult to identify & separate “gas bubbles” from “crystal fingerprints” but with few practice one can easily separate between “gas bubbles” and “crystal fingerprints”.

    Blue sapphire (variety of corundum) is generally heavier than all these stones (Iolite, Tanzanite, Benitoite & Man-made Blue glass) except Synthetic Cubic Zirconia (C.Z.). That is, if the same volume of these gemstones are weighted blue sapphire will weight heavier.

    Refractometer is an instrument which checks the R.I. (refractive index) of gemstones. It is a “life saver” for many people involved in gemstone trade. One can separate more than 50% of the gemstone solely on the basis of this small instrument. I personally suggest everyone involved in this field to buy this instrument.

    A word of caution: If you are even 1% unsure whether your gemstone is genuine or not then it is highly recommended that you get it certified from a reputable/trusted gemological lab.

    Updated On: December 14, 2012: Added Synthetic Cubic Zirconia as a substitute for Blue Sapphire and made minor correction to the post.


    Thanks for valuable information.



    I am sending you a ebay web link of the gem which I bought from a seller and could you please tell me by judging from pictures whether it is real or fake gem.


    UPDATE: Link has been removed as ebay has removed the listing page.


    The gemstone shown in the above link should be blue sapphire.

    Since this gemstone is very clean it is not possible to make out whether it is natural or synthetic under the basis of picture.

    Sapphires (mostly yellow and blue) which comes from Bangkok (Thailand) are mostly heat treated. Even “natural colorless sapphire” are converted to “natural blue sapphire” with heat treatment.


    Thanks….you mean to say that it could be synthetic ?


    Generally, heat treatments are done in “natural gemstone” but heat treated “synthetic gemstone” are also available in market. Since your blue sapphire is said to be heat treated so it should not be synthetic but this should not be taken as confirmatory. Only a gemological lab or expert in gemological field can ascertain whether your stone is natural or synthetic after instrument testings.

    “Rule of Thumb” – If a gemstone is very clean and price is very low then chances are that the stone is synthetic / fake.


    To identify the original sapphire easiest way is to verify through Magnifying glass. If it is original the inner structure of sapphire is little messy but the synthetic sapphire looks very straight and ordered.

    Similarly the easiest way to identify the synthetic Loose Diamonds is same but we cant relay only on magnifying glass.


    I have purchased this stone and the vendor has given me the certificate also they have given in writing through official email that this stone belongs to Ceylon. I have tested through a local lab and they have even mentioned that it is a natural one.

    But when I see it in light i do not find any inclusion. When spoken to the dealer they mentioned that they cut in such a way that the inclusion part is in the corner any due to cutting the small inclusions get hidden in the shadow. Please let me know your thoughts. Thanks.



    Not all natural blue sapphire will show you inclusions. A lapidary cuts a stone in such a way that inclusions are hidden near girdle and culet making top facets part clean and clear.

    If your gemmological lab says it is a natural gemstone then it can be but it is very diffcult for even gemmological lab to verify the origin of gemstone.


    I inherited an oval blue sapphire from my grandmother who received as a gift from grandfather sometime between 1935 and 1954. It’s a rich blue color, about 2+carats with six small diamonds flanking (3 each side), set in 14k white gold. From what I know, grandfather was a jeweler for some time during that period in Philadelphia, located in Jewlers row.

    I don’t know if it is a natural stone and my question is, were lab created stones prevalent back then? The stone is very brilliant blue and seems to be very well cut. Any insight would be appreciated. 



    The first lab created gemstone was made during 1890’s using a flame fusion process. Initially it was only used to make ruby and all color of sapphires but later it was used to create many other gemstones.

    Though, there were significanly very few lab created gemstones available in open market at the time of 1940’s but I would suggest you to get your gemstone lab tested.


    Hello, I am looking at this Ceylon Blue Sapphire Ring and would like your opinion on the price. I believe the website provides appraisal service as well. The sapphire is eye clean and about 2 ct.

    Thank you!!!

    UPDATE: External link has been removed as it is not working anymore.



    In ZeeXchange website it is written Gemstone as Natural/Enhanced this means that gemstone is Natural but it is treated (enhanced). The treatment is not mentioned there but most likely it is either heat treated or diffusion treatment. These kind of treatment can even turn white sapphire into blue sapphire, so paying $3,200 for a treated 2 carat stone is not worthy.

    And, if someone is selling Ceylon Sapphire from Thailand then it is most likely heat of diffusion treated. Ceylon blue sapphires are actually mined in SriLanka so when you are purchasing Ceylon sapphire it should be untreated and its origin should be Ceylon, SriLanka, otherwise there is no use in buying a Ceylon blue sapphire.

    I would suggest you to go to to search for your blue sapphire and please avoid sellers from Thaliand (Bangkok).

    I don’t know how trust worthy these ebay-sellers are but their blue sapphire looks pretty good for the price & quality:


    Thanks a ton for answering so many people . . . .

    I am one of them 🙂 and have recently brought a blue sapphire which cost me Rs. 3,200 ($60) I too see color zoning in it. Please let me know if the original Neelam (blue sapphire) would cost so less.


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