To examine the relationship between siliceous sinter and epithermal gold mineralization, sinter samples were collected from thirteen locations in Japan. The samples were analyzed by X-ray diffractometry and X-ray fluorescence spectrometry. The samples were also analyzed by inductively coupled plasma mass spectrometry (ICP-MS) for the quantitative determination of gold. The dominant silica minerals change from opal-A (younger than 10 ka), through opal-CT with quartz (10 ka to 1 Ma) and finally to quartz (older than 1 Ma). Most sinter in the distal location from the discharge site contains less than 0.02 wt % TiO_2 and 0.5 wt % Al_2O_3. Higher concentrations of TiO_2, Al_2O_3 and K_2O can be explained by contamination of detrital materials. The concentration of gold in sinter ranges 0.1-827 ppb and shows a bimodal distribution, which corresponds to gold mineralization.
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