59-carat untreated, unheated Madagascar blue sapphire, we're talking about an exceptionally large Round Cut specimen that would be considered museum-grade or investment quality. Stones of this size are extremely rare, especially without treatment, even semi translucent with minor issues.
Given the specifications:
59 carats (extraordinary size)
Untreated/unheated Madagascar origin
SI2 clarity with some surface issues under the table
Semi-translucent with good light response with Gemstone torch
Excellent cut
Not Filled
A natural untreated blue sapphire of this size would typically command anywhere from $3,000-$8,000 per carat depending on color saturation, overall clarity, and certification authority. At 59 carats, this would put the retail value range approximately between $177,000-$472,000.
The semi-translucent nature and surface issues would place it toward the lower end of that spectrum, but the excellent cut and knowing your owner cut the stone from the rough and thats it adds positive value factors.
These extremely large sapphires often sell through high-end auction houses or to specialized collectors rather than through standard retail channels. The market for stones of this exceptional size is quite specialized, and finding comparable stone would be challenging, the stone would make a large ring or pendant, and again this is a natural unteated unheated not filled massive Madagascar Blue Sapphire Stunning
                                       .FREE FEDEX POST WORLD WIDE.
Unlike many other we only sell natural untreated gemstone bought in the rough and cut by our owner, on occassion we have vintage stone bought in or stones cut by locals in Gemstone mine areas around the world.