I have a .stl file that I want to import into a Graphics3D expression, for which I use the command
Import["ExampleData/seashell.stl", "Graphics3D"]

As you can see, the color function mainly consists of pink and purple, and I want to change it.
Adding the ColorFunction option to the Import command doesn't make any change:
Import["ExampleData/seashell.stl", "Graphics3D",
ColorFunction -> "TemperatureMap"(*for example*)]
How can I change the color appearance of the 3D object?