Visual Signs:

* Color Changes: Weathering can alter a rock's original color.

* Oxidation: Iron in rocks reacts with oxygen to form rust, giving it a reddish-brown hue.

* Lichens: These organisms can stain rocks with various colors.

* Surface Texture:

* Roughness: Weathering can create a pitted, uneven surface.

* Smoothness: Wind and water can smooth and polish rock surfaces.

* Fractures: Weathering can create cracks, fissures, and breaks in the rock.

* Shape:

* Rounded Corners: Angular rocks become rounded over time as edges are worn down.

* Unusual Shapes: Weathering can create unique and irregular shapes.

* Deposits:

* Salt Crystals: Evaporation of water can leave behind salt crystals, which can break down rock.

* Mineral Staining: Dissolved minerals can leave behind stains and coatings on rock surfaces.

Other Indicators:

* Presence of Soil: Weathering is a key process in soil formation. The presence of soil around a rock suggests weathering.

* Presence of Plant Life: Plants growing on or around a rock can contribute to weathering through their roots and acids they release.

* Evidence of Erosion: If a rock is located in a place where there's evidence of erosion (like wind-blown sand, water flow, or landslides), it's likely been weathered.

Remember: The degree of weathering can vary greatly. Some rocks may show only subtle signs, while others may be severely altered.

Important Note: To truly understand the extent and type of weathering, it's often best to consult with a geologist or someone with expertise in rock formation and weathering processes.