Vinyl manufacturers are getting better and better at imitating the look of genuine leather products. Distinguishing between a grain-printed piece of vinyl from a real piece of leather just looking at it can be a real challenge. But there are several ways to tell if what you're looking at is real leather or a just a great imitation.
Look at the underside of the item. Leather has a fuzzy, suede look on the flip side. Vinyl has a thin cloth mesh. Look at the exposed edges of a piece of furniture's upholstery so you can peek at its underside. If you're looking at a leather jacket or other piece of clothing, try to find an inside area not covered by a lining.
Smell the item. Leather, made from animal hide, has a distinctive, organic smell. Vinyl either has no smell, or smells like plastic.
Feel the texture of the item. Vinyl is quite smooth, especially on older furniture. Leather has a grainy texture you should be able to feel, although some types of vinyl have grain stamped into them. Leather generally is softer to the touch than vinyl.
Pinch the material. Leather stays peaked for a little while after you release it; vinyl will return to its original shape.
if none of the other steps are conclusive, hold a match near an inconspicuous spot of the material. Vinyl will start to bubble and melt, whereas leather will scorch. Obviously, this will damage the material, so only do it if you really need to find out which one you've got.