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<br />1 <br />' Diamond drill core samples driI_~,~ ~,y Murray »atts Drilling <br />Co. at Hendricks Mining Co.'s Cross Gold Mine at Caribou, <br />' Colorado in 1990. <br />Depth Below Surface - Approximately 400 Feet <br />Core Size - Nx 2" Diameter <br />' TPrtiarv Caribou a o- Mod-oni e <br />Geologic Time <br />Cenozoic Era - Paleooene Epoch + 63 milli ors years old ~,6 million <br />' years a6 reported by Aelores Gable in Professional <br />Paper 1280 USGS <br />Monzonite formed about two miles below surface from a molten <br />' magma. It is bluish gray medium grained rock composed essential- <br />ly of feldspar, biotite, augite and andesine. Feldspars are <br />nearly five times as common as quartz and are aluminum silicates. <br />Hornblende forms thin seams along joint planes. Monzonite has <br />an approximate hardness of 6 and a specific gravity of 2.6. <br />Specific gravity being the relative weight of a mineral compared <br />t to the weight of an equal volume of water. Gold has a specific <br />gravity of 19.3. <br />[~~noai +en <br />' Plagioclase Feldspar 30-5D9 Na, Ca, feldspar <br /> Orthoclase 10-309 Potash feldspar - adularia - <br /> bluish sheen <br /> Biotite Z-109 Dark colored - mica - silicate <br /> mineral of magnesium ~ iron <br /> Augit® 1-59 Pyroxenea - a mineral group <br /> ABSipOy where A is chiefly Mg, <br />' Fe, Ca or Na and B is chiefly <br /> Mg, Fe or Al - iron silicates <br />' found in nearly all igneous <br />rocks t <br /> Andesine 1-59 Albite Na AISi3O8 <br /> Andesine s ---middle <br />' Anorthite CaA12Si2Og <br /> Hornblende Amphiboles - compllex hydrous <br /> silicates - hornblende + <br />' aluminum <br /> Monzonite will not decompose easily. It will retain both heat <br /> and cold for prolonged periods. The idea of making a monzonite <br />' rolling pin was given to me by CU graduate student Beth Aeidt <br /> when she toured the Cross Mine on October 21, 1990 with an adult <br />' education class. <br /> I hope you enjoy your g iece of geologic time. <br />' <br /> Thomas S. Heridricka <br /> Caribou, Colorado <br /> <br /> <br />