Select Color in the Mesh Inspector's Mesh Color section to change the displayed color of the selected Surface Mesh.
Use the hue ring and color field to select a color visually, or enter precise RGB or hexadecimal values. The previous-color control returns to the previously applied color, while the current-color preview shows the active selection. Reset in the Mesh Color section restores the color assigned when the mesh was imported.

The Mesh Color picker with RGB and hexadecimal controls.
Surface meshes are assigned a random color on import, which can then be customized without changing the source geometry.
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