Erythrite (Hydrated Cobalt Arsenate)

10x
Erythrite (Hydrated Cobalt Arsenate) Co3(AsO4)2-8(H2O)
Location source = Sonora, Mexico
Purity = Unknown. Because it is a mine run rock there is likely a large variety of associated minerals.
Size rock = approximately 2” square
Size of area in focus (center) that below test originated from = approximately ¼”
Image captured with B&L SZ5 microscope, coupled to a ccd camera and computer.
Color is almost correct, but a little more red would be more accurate.

Erythrite (Hydrated Cobalt Arsenate)
Image taken with 35mm camera and a 135mm lens, set at macro for close-up focusing, shutter speed = 1/125th of second in shaded sun using 200 film and developed by Kodak 1 hour commercial labs and then digitized.
Size of sample being subjected to propane torch oxidizing flame = 3/16" long, 1/8th wide, 1/32" thick
Sublimate color = accurate, but has nearly vanished after sitting on a table at room temperature for 10 days. Obviously, there is a very volatile component element and I doubt that it is only arsenic. Even the sublimate on plaster tablet provides clues as to the over-all volatility, because there is no sublimate close to the sample rock (scraped crystals) being heated and very little heat generated cracking of the plaster tablet.

40x
Erythrite (Hydrated Cobalt Arsenate)
Image captured with B&L SZ5 microscope, coupled to a ccd camera and computer.
Color =
Notice how the knife scrapings of the reddish crystals have altered when the oxidizing flame was applied forming a radiating crystalline structure. This particular crystalline mass will have to examined further with fluxes to determine how much arsenic remains with the Cobalt.