Smectite Group
Perch Point-Potholes Reservoir, Warden, Grant County, Washington, USA
Filamentous bright yellow threads of smectite group clay in a basalt vesicle. This filamentous clay occurs often in the basalts of my area and comes in a variety of colors including white, yellow, orange, green, brown, blue, purple, and black. Yellow is by far the most common color. A good guess would be that this filamentous clay is either ...