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Materials Processing Laboratory
The Department of Mineral Sciences Materials Processing Laboratory is uniquely equipped for cutting, grinding, polishing and sampling of a wide variety of material types and sizes. The laboratory includes a 10 ton capacity wire saw, abrasive and diamond saws up to 24 inches in diameter. Cut surfaces from very small to square meters in size can be ground and polished.
Meteorites and rocks from around the world have been prepared in the lab. Many examples of these can be seen in the Janet Annenburg Hooker Hall of Geology, Gems, and Meteorites. Most of the work currently done in the lab is in the support of ongoing scientific research or collections management.
- An example of an exhibit case in the Geology, Gems, and Meteorites Hall showing a number of large rocks prepared in the lab.
In addition to meteorite, rocks and minerals, materials from other Smithsonian as well as outside agencies are prepared in the lab. These materials include petrified wood, dinosaur tracks, whale teeth, mollusk shells, human and animal bones, archaeological ceramics and metals, and many others.
- Cutting of a very large banded iron formation specimen from Michigan using the wire saw (left image). The banded iron formation specimen in the Earliest Life exhibit in the National Museum of Natural History. The polished face is 5.5 feet high and 8 feet wide.
- The 10 ton capacity wire saw being used to cut the 5000 pound Old Woman meteorite from California. The saw uses abrasive slurry of garnet and water to slowly cut through a specimen this size. As many as 75 wire changes over the course of several weeks are required to cut an iron meteorite this large.
- Grinding the surface of the Old Woman meteorite (left image). Grinding and polishing of large rock surfaces is done with a series of seven 5 inch diameter diamond disks. After grinding the surface of iron meteorites, a solution of 5% nitric acid in alcohol is used to etch the surface. Etching reveals the internal crystal structure which is the result of millions of years of slow cooling.
- These enormous petrified logs from Arizona are on display outside the Museum of Natural History. They were cut, ground and polished in the Materials Processing laboratory located in the part of the building in the background on the ground floor.
- This 24 inch abrasive saw was installed in the lab specifically for the cutting of iron meteorites. Rapid cutting and smooth surfaces are made with minimal loss of material and minimal damage to the cut surface of the meteorite.
- This 14 inch water-cooled diamond saw is the most heavily-used piece of equipment in the lab. Hundreds of rocks collected by Department of Mineral Sciences geologists each year are sliced for chemical analysis.