Very fine gemstone: large Tanzanite - 61.43 ct. Merelani Hills, Umba Valley, Lelatema Mountains, Arusha Region, Tanzania. Photo courtesy Heritage Auctions

Luscious is a term that comes to mind when looking at this Tanzanite. Other superlatives might be big or huge. At 61.43 carats this is a very impressive gemstone with excellent color: it has the rich blue hue with just a hint of purple that Tanzanite is renown for. When examined this stone exhibited flashes of red, so it would be a fair assumption that it has not been heat treated. Fashioned as a large cushion, it would certainly make a statement if fashioned into a custom piece of jewelry. 
Measurements: 24.4 x 20.17 mm, 61.43 ct. Estimate: $55,000 - $75,000. 

Heritage Auctions. 2013 Oct 19-20 Nature & Science Signature Auction - Dallas #5141