Tanzanites

My nephew has acquired some Tanzanites from the USA with a promise for more, (he has friends there). I have no idea what quality, shape, size, cut/uncut, cabochon or facetted they are, but he wants to sell them and doesnt know where to start. I have told him that if they are nice ones depending on price I will have a couple, but as I normally buy from recognised sources I have to rely on others to tell me if they are good. P.S He knows nothing about stones apart from they are Tanzanites, and I havent seen them yet. I suggested he sells them on ebay, unless anyone on here wants some, but I stress I dont know what quality they are.