https://www.britannica.com/biography/Mahmud-I

But further details of how it came to Sultan Mahmood/or made by him? is missing. He was a famous Sultan of the Ottoman Empire.

While I check up on that any one who knows about it is free to post.

https://www.internetstones.com/topkapi-emerald-dagger-museum-hollywood-heist-film-palace-35-cm-sultan-mahmud-i-nadir-shah.html

Stanley Tan
February 7, 2010 at 7:01 am

Hi, I am from Malaysia. Recently, I discovered a rare gemstone from our State.The hardness of the stone is 7.5 to 7.8. However, our local lab has named it as a carnelian. But, I checked the internet and I found that there are no records of our country having this type of gemstone. Please I need your comment.Thank you.

Suhail
February 18, 2010 at 3:52 am

Wow what an excellent article !!!

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Jennifer Page
October 14, 2009 at 6:43 pm
My mother, Beverly Pollard Page, is Mrs. Logan’s niece. As a child we visited “Aunt Polly” (Rebecca Pollard Guggenheim Logan) in Washington DC and her donated sapphire at the museum.

The following answer was provided by me on April 1, 2009 :-
Hello,
Thank you very much for the question regarding the black star sapphire.
Actually it is not known for how much the stone was sold by the anonymous owner in 2002.The estimate of 100 million dollars was quoted by several leading newspapers, but they did not quote their source either.
Considering the enormous size and the perfect star, I am not surprised at the estimate.
Take a look at the current prices of black star sapphires:These are the prices of smaller black star sapphires.
>1.0carats 3 to 10 US$ per carat
>1.0–4.99carats 10 to 50 US$ per carat
5.0carats + 30 to 100 US$ per carat (golden stars may reach US$ 200 per carat).
The Black Star of Queensland is the only large black star sapphire in the World, it is the only one of its kind in the world.There are numerous large star rubies and large star blue sapphires in many museums and private collections of the world.
The usual sizes of black star sapphires is less than 5 carats, making the black star of Queensland an extremely rare gemstone.It is highly unlikely that another one of this size will be found even in the future.
In my opinion it is difficult to estimate the present value, being an extraordinary stone it cant be compared to market value, because black sapphire stones of such enormous size and quality are not available in the market. The price will be determined by the highest bidder (auction) for the gemstone.
Please feel free to contact me if you have any further questions/comments on this gemstone or any other gemstones/diamonds - Dr Shihaan

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Posted by Setillia
January 2, 2009 at 3.17 am

This article, although quite informative, also seem to be biased in saying that a sapphire that is "Kashmir" is somehow better than other sapphires. I beg to disagree. A sapphire of exceptional fire and radiance can be found from any number of locations world wide and in fact, many reputable sapphire experts agree, that one can only guess where a sapphire has come from and just because it appears to be from a certain location does not mean it truly can be determined without any doubt.
Burmese, Sri Lankan, and Thai sapphires have in fact demonstrated such colour and intense "Kashmir" qualities, and today, sapphires that show such qualities are called ‘Kashmir’ when being referred to and it only means the actual look of a sapphire but has no connection with their origins. Since we now know that origin of sapphires is very difficult, if not impossible to determine without the slightest doubt, saying a "Kashmir" sapphire is better than the rest may be true, if the reference is to a stone’s appearance, and not to its origin. For those who still insist that the term "Kashmir" should only refer to stones originating from Kashmir, good luck to them as they go about in trying to prove that their gemstone actually originated in Kashmir and not other reputable locations such as Burma, Thailand and Sri Lanka !!!

Ed Borgatta
June 27, 2010 at 9:20 pm
There is a major error in the identification of the contributors of the American Golden Topaz to the Smithsonian Museum. The identifying museum card correctly states:
“Gift of the Rockhound Hobbyists of America through the efforts of the six regional federations of minerological societies and Drs. Marie and Ed Borgatta, 1988″ The Borgattas were the major contributors of the Topaz.