Nicholas Wetzel S. M. Heinrich B. R. Lipin 1983 <p>The Emma Bell chromite deposit in Siskiyou County, California contains over 5 million tons of dunite averaging about 4 percent Cr₂O₃. Chromite is not evenly disseminated throughout the dunite, however. For the most part the deposit consists of many chromite-rich bands in sharp contact with, and separated by, common dunite containing 1 to 2 percent accessory chromite. Electron microprobe and petrographic analysis of accessory chromite shows that it is fine grained (average grain size 0.14 mm), generally lower in Cr₂O₃, and has a lower Cr/Fe ratio than segregated chromite. In addition, unusual patchy zoning is exhibited by some accessory chromite. These patchy zones are extremely rich in iron (&gt;60 percent total iron oxide). The negative factors such as the fine-grained nature of the accessory chromite and high iron content compared to segregated chromite, could be overcome by the very large tonnage in the deposit.</p> application/pdf 10.3133/ofr83816 en U.S. Geological Survey The Emma Bell deposit, Siskiyou Co., California: A possible low-grade source of chromite reports