Boulders & Slabs ; Large boulders are used as landscape and water features and are also commonly incorporated into retaining walls. Slabs can be used for bridges, ramps and other uses. Deep Creek BouldersJuly 17, 2017 Pipestone Granite BouldersFebruary 21, 2017 Quartzite BouldersNovember 9, 2022 Flatwillow BouldersFebruary 21, 2017 Kootenai BouldersFebruary 21, 2017 Chief Cliff BouldersFebruary 21, 2017 Stillwater BouldersJuly 28, 2017 Frontier® SlabsFebruary 21, 2017 Tin Cup Basalt BouldersAugust 28, 2017 Prairie Fieldstone BouldersFebruary 21, 2017 Basalt ColumnsAugust 28, 2017 Cabinet Gorge BouldersFebruary 21, 2017 Colorado Buff BouldersFebruary 21, 2017