Scraper, Stone Item Number: 1-10868 from the The Burke: University of Washington
Chip. Locality: Quartermaster Harbor, Vashon Island. Remarks: Site 13.* Pink color, triangular, tapers to a point. *Information is from the original accession ledger. The following artifacts were analyzed by Elizabeth (Betsy) Scharf. 1-10868, 1-10889, 1-10919, 1-10934, 1-10951, 1-11010, 1-11013, 1-11037, 1-11044 Her analysis is described below (August 10, 1999). "I used the SEM and microprobe (xrays emitted from the rock when bombarded with electrons) to analyze the lithics. What I found was that some had small hematite crystals embedded in cryptocrystalline silica. Some samples were just cryptocrystalline silica with no other materials embedded in them. The bulk composition was silica. Of the cations, silica composed 98%, Fe was about 1% overall, and other ions accounted for the rest of the material. (I picked a typical sample -- there is some slight variability). But these samples are VERY siliceous. The texture was microcrystalline, just like chert. One sample had a small piece of a diatom left, so I think these are diatomaceous cherts. I am not sure if they are freshwater or salt, but they must be shallow water since the Fe is red in color (oxidized) like rust. The samples had only trace amounts of magnesium, which to me indicates a freshwater source for the diatoms. I'll vote for eastern Washington, a diatomite area. But I don't know, offhand, of a red one. Perhaps red "opal" or "jasper" is a better term for the material, but "red chert" suits me fine. The "grainy" appearance of some of it is due to little euhedral crystals of hematite growing in some of the background of cryptocrystalline material. Compositionally and microscopically, it fits the green opaline materials I collected from diatomite pits in Grant County. The bulk compostion of the "opals" were 96% Si and 3% Fe, plus trace elements. The only difference was that the opals looked different to the naked eye in color and perceived transluscence. Red obsidian, in comparison, lacks all crystals and contains significant proportions of K, Na and Al. Obsidian= 75% Si, 2% Fe, 8% K, 2% Na, 11% Al. Our samples had only trace amounts of K, Na, Al, Mg, Ca or Ti, so I'd say our samples are NOT volcanic. (So let's rule out the ashes and tephra, too). There's just not enough K, Al, or Na to make feldspars or mica from!"
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Purchased from E. O. Roberts