James Goss-

Guardians
Basalt

Columbia River Basalt

Starting in early Miocene time and continuing into the early Pliocene, tremendous volumes of basaltic lava, named the Columbia River Basalt Group were extruded across the Columbia Plateau region. The molten lava flowed over thousands of square miles, with some flows travelling over 200 miles from their source vent. Along the marginal areas of the expansive lava field, the flows dammed the peripheral river valleys. Many of the stones from my quarry show the effects of glaciation and water erosion, "mother nature's" carving tools.
colors range from steel gray to copper brown and black