[Slicksadick]

Heres a guy who actually sells the columns for landscaping. Very cool.

Marenakos Columbia River Columnar Basalt

Available forms:	2’ - 19’ columns, and Dish Rock. (Over 19’ special order).
Also available as:	Columbia Premium Landscape
Characteristics:	Natural occurring shapes, mostly hexagonal. Diameter typically 24” - 42” range. Exterior color: Medium to dark brown. Interior color: Black
Uses:	Water source stones, entry way monuments, vertical elements, benches, and small retaining walls. Can be custom cut, custom core drilled.
*NOTE: Typically weighs approximately 1,000 lbs. per linear foot. Special handling may apply to this stone.

[cogitator]

I wonder where the quarry(s) for columnar basalt are located. The most picturesque occurrences are probably parks, but there's a lot of basalt out there.