URUACU

THE 10TH SPHERE OF MY COLLECTION

COMPLETED OCTOBER 5TH, 2007

A gold prospector named Don contacted me about processing fees, he had some Uruacu meteorite fragments. I gave him a rough estimate & also mentioned that if I liked the look of the material I might be interested in some of it for a sphere. We worked out an agreement that was mutually beneficial & he sent 14 kilograms of fragments to me for processing. I quickly sliced up part of a 7kg fragment & etched a few slices. I REALLY liked the material. Normally I wouldn't make a sphere from a material classification that I already had but even though Uruacu is chemically similar to Campo, it's structure is very different. I decided to make a sphere from it and worked out an arrangement with Don. I finished processing the 7kg fragment & sent the rough to my machinist. During the machining process the "nub" that is used to hold the rough in place sheared off. Without anything to clamp to, my machinist's only recourse was to return the unfinished sphere to me. It was about 85% cut but I had no way to finish it, see the below image.

I contacted John at The Rare Earth Trading Company and asked if there was any way he could finish it. He said they could hand grind it into a rough sphere before he could finish it up on the machine. I sent it to him and patiently waited. They were able to finish it but were not able to maintain the 50mm diameter, this was both good and bad news. John sent it back to me so I could polish & etched it. It looked like it was going to be awesome which made me feel even worse since it was a lot smaller then the rest of my collection. There was another fragment that I had not processed yet so I asked Don if I could use it to make a second sphere. He had no problem letting me use more material even after I told him we would not make much money selling the first sphere. I sent John the new fragment & finished the 48mm sphere. It was awesome so I sent Don the below pictures & he loved it. I asked him if he wanted it instead of a slice which is what he originally wanted as part of our arrangement. He did, so I sent it to him & it now resides on his computer desk :)

The second fragment was too small to machine so I sent it to John for hand grinding. He as successful in turning tit into a 51mm rough sphere & returned it to me for finishing. I quickly polished and etched it. I was amazed at the way it turned out. It's loaded with inclusions & veining. Even though there is not a lot of contrast to the etch it is very unique. This sphere is my favorite so I'm glad that I didn't give up. I also appreciate Don giving me a second chance even though he knew we would make less money by using a second fragment. Don is a Gold Prospector but if he ever decides to become a meteorite hunter he will be a great asset to the community.

Name: Uruaçu - This is an OFFICIAL meteorite name.

Observed fall: No

Year found: 1992

Country: Brazil

Mass: 72.5kg

Classification: IAB-MG / Course Octahedrite

Circumstances of the fall or discovery: Four masses have been recovered: Mass 1 -29 kg, Mass 2 - 25.2 kg, Mass 3 - 300 g, and Mass 4 - 18 kg, on the property of Mr. Wilson Rezende. Mass 1 was found by a cattleman in 1992, masses 2 and 3 were found in 1994 and 1999 respectively by Célio Rezende, and mass 4 by miners prospecting for gold in 2000. Classification (M. E. Zucolotto, MNRJ; J. Wasson UCLA): Bulk composition: Co = 0.46%, Ni = 6.43%, Ga = 89.6 ppm, As = 11.6 ppm, Ir = 3.36 ppm, Au = 1.46 ppm. The composition is indistinguishable from Campo del Cielo. It is a cohenite-schreibersite-rich iron.

Source: Meteoritical Bulletin, no. 86, MAPS 37, A157-A184 (2002)