Keywords: Opal polished.jpg 3 cellspacing 0 align center style border 2px solid seagreen; margin 1 5em 0em 1 5em 0em; + style background seagreen; color white; Polished Opal - background lightgreen; padding 0px 15px 0px 7px; border-right 2px solid seagreen; Taken by Aram Dulyan User Aramgutang align right style padding-left 5px; Date 22'FEB 2005 - 4 style background mintcream; padding 0px 15px 0px 7px; border-right 2px solid seagreen; Polished iridescent opal on trachyte from ÄŒervenica Slovakia Photograph taken at the Natural History Museum London align right style padding-left 5px; Camera Canon PowerShot A75 - align right style padding-left 5px; ISO 100 - align right style padding-left 5px; Aperture F 3 5 - align right style padding-left 5px; Shutter speed 1/10 s Aramgutang Opal Trachyte Minerals of the Natural History Museum London Geology of Slovakia |