http://rockhoundblog.com/regular-postings/spring-rockhound-run-black-agate-thunder-egg-mine-pebble-terrace-opal-hill-mine-and-black-hills-geode-beds/ rockhound, minerals, science, geology, rocks Thu, 09 Apr 2009 05:20:57 +0000 hourly 1 http://wordpress.org/?v=3.0.1