https://www.google.com/maps/dir/Duvall,+King,+Washington/47.801899,-121.940787/47.811627,-121.941891/47.818054,-121.941848/@47.7879417,-122.0334479,16775m/data=!3m2!1e3!4b1!4m14!4m13!1m5!1m1!1s0x54900ac5c8d571df:0xc73986cc56f4c3fc!2m2!1d-121.9856781!2d47.7423218!1m1!4e1!1m1!4e1!1m1!4e1!3e0?hl=en
Minerals of the Tower Hill Quarries, Snohomish County, Washington, USA (washingtonminerals.com) Mount Persis Andesite - Tertiary. Hydrothermally altered andesite, varying in color from gray (less altered) to yellow, red and brown where heavily altered. Voids created by faulting and brecciation have been partially/completely filled by hydrothermal mineralization.
Helpful notes to newcomers: there is no water, so it is a good idea to bring your own to wash off the rocks…if the gate is open I would suggest bringing a bucket of water with you. the dirt is a sticky red mud. bring shovels too.
Tower Hill Agate Rockhounding Monroe Washington (youtube.com) #towerhill #towerhillagate #melanophlogite