smooth river stones with natural patterns

river stones natural patterns smooth textures earth tones nature geology pebbles rocks materials abstract background textured earthy organic landscape outdoors tranquil serene zen formations patterned landscapes geological wonders backgrounds minimalist design calming vibes zenlike aesthetics bed treasures tactile surfaces muted color palettes symmetry soothing weathered elements rustic simplicity meditative moments understated beauty artistry elemental essence grounded energy peaceful ambiance ai generative generated synthography