I am trying to find out the value of a
This is a natural (untreated) color changing 10+ carat Sri Lankan blue/grey star sapphire I bought for $2000 wholesale over 20 years ago at the Tucson show. It seems I can’t find color changing star sapphires as a category for pricing. I am wondering what it’s worth today.
Hi Jonathan! Welcome to the forum!
The stone is showing very strong asterism! It is a very nice looking star sapphire. Based on the color in the image and descriptive settings entered in GemVal, here are two different price points based on various clarity ratings:
Of course, these are based on only a few observable features and from a single image. Therefore, the values from GemVal are suggestive and may not provide the best range. Also my observations might not have provided the best selections and should be considered very subjective. 
It would be best to have it appraised by a local gemologist in your area.
Cheers!
That’s nice to know. I’ll take to an IGA appraiser in the city. Thanks for the response and ballpark estimates.
You’re welcome! Hope the appraisal is in your favor!
Would be curious to know how well the GemVal numbers do in comparison.
Troy. I know that this is not in relation to the original post, Thank you for your response to Jonathon’s post. I also use GemVal for my stones, (going on 9 years now) yet still have a lot of doubt as to their true worth and validity, (real or lab-made). Therefor I haven’t sold any of my collection as of yet, (over 500 stones). I in NO WAY want to misrepresent a stone as natural, that is lab made and vice-versa. I am at a loss, and therefore standing still. I hope and pray that Jonathon K’s stone is worth what GemVal says it is. And mine too. LOL.
Hi Lue. Thanks! Have been very curious on how well GemVal tracks with other resources. Been wanting to compare notes with others on its accuracy, so I hope Jonathon’s appraisal can shine some light on the question.
I am impressed on how GemVal keeps track of a collection and updates the valuation based on current industry info. Just not confident in the price points, since very few scoring criteria is used to provide a value.
Jonathon (@JonathanK94858 ) must apologize up front for volunteering you to be a subject in my impromptu science experiment… 
Looking for other “volunteers” as well. 
I do have a few out for appraisal, so I will post my notes when they are complete.
Cheers!
