It is not actually that tough to differentiate between a Metallic Paint and a Solid Paint on a vehicle. Others have already explained the difference between them -:
Metallic colors are sparkling and their surface is different than the one in solid colors, Due to the mixture of Aluminum flakes etc mixed, As Aditya said. Solid colors are plain and simple which we saw in old time’s ambys.
Metallic shades have gradually become popular among buyers because of their glossy finish and up-market touch. It is generally indicated on automobile websites/brochures about Metallic and Solid color by an asterisk (*).
Another advantage of Metallic color is that they don’t tend to show the scratches on vehicle’s body easily. However, They are comparatively expensive to maintain and there is a difference of few bucks if you buy a car with Metallic color. I remember when I casually asked at Maruti Authorized showroom the cost of repainting the car (800) from solid to metallic color, The price I was told of solid color was Rs.15,000 and Metallic was Rs.21,000 but mind you, These figures are around 5-6 years old.
Drive Safe,
350Z