http://www.ebay.com/itm/Heavy-Gold-Plate-Unfinished-Semiconductor-Scrap-For-Recovery-Purposes-/190753784091?nma=true&si=bNCanv6ryYTbpUjqmOc4CjOdJIA%3D&orig_cvip=true&rt=nc&_trksid=p2047675.l2557
http://www.ebay.com/itm/Heavy-Gold-Plate-Unfinished-Semiconductor-Scrap-For-Recovery-Purposes-/190754556238?nma=true&si=bNCanv6ryYTbpUjqmOc4CjOdJIA%3D&orig_cvip=true&rt=nc&_trksid=p2047675.l2557
These 2 did sell. Scroll down on both pages for the description.
The first is a heavy 64 lead side braze package. The ceramic (alumina) is about 3.25" x .75" x .0625" and the density of alumina is about 4 (I'm not sure about the alumina thickness and it could be a smidge thinner, in which case they would be a smidge more valuable). That would make them weigh about 10.5 - 11g with the lead frame or, about 41-43 parts/pound. The plated area is about 2 - 2.25 square inches. The gold thickness is about 45-55 microinches or about $.77 - $.95/square inch. That would make them worth about $63 - $92/pound. They sold for $132/pound. I haven't plated any of these 64 leads, but I've plated several million (literally) of the 40 lead variety, which are identical, but smaller, and only about 40-45% as heavy.
The 2nd one is an all gold plated flatpack package. The plated area is about 1.75 square inches and the plating is about 50 microinches thick or, $.86/square inch. The total weight is 0.84 pounds and there are 102 parts. That would make them worth about $183/pound. They sold for $363/pound.
I could be off a little on the 3 parts I've evaluated, but I doubt if it's more than +/- 10%. The 64 lead side braze could be off a little more due to inadequate information. You would have to refine them or assay them to know the exact numbers. The soft gold on all of these is 99.99% pure, unlike the hardened alloyed gold on fingers, which averages about 99.7% pure. The reason the gold is about double the thickness of that of fingers is that all 3 must be heated to around 540F to 700F in order to attach the chip, lid, or hybrid circuit. If the gold were thinner or less pure, it could discolor when heated. These parts (all 3 are called packages) have never been used and they are, for some reason, rejects from a semiconductor facility. They would be worth more if they had circuits and lids that were attached with gold braze.
